Twinship and Marriage – Experiences during the Course of Twin Relationships

The aim of this study was to explore and describe older twins’ experiences of their marriages in relation to the co-twin relationship. Material and Methods: The material consisted of 34 life story interviews with older twins (70+), representing various experiences of twinship and marriage. The data was analysed with qualitative latent content analysis. Results: Phases of marriage describe the time of Courtship partners were chosen based on infatuation. Most were non-related, but some were relatives or friends. Twinship and quality of married life showed that marriages were either disharmonious or harmonious. The most common cause of conflicts was spouses not getting along, second common cause to conflicts was the twin relationship itself. In the harmonious marriages, the spouses were sympathetic and accepting of the twin relationship. In later life 14 of 34 were widowed and 7 of 34 had gone through a divorce. The most common cause of divorce was an unfaithful spouse, rather than the close relationship with the co-twin. In difficult times the twin relationship served as a source of comfort and support. Conclusions: The most harmonious marriages were with spouses related to one another. In this way the twins could keep both the twin relationship and have a marriage. Since twins often regard each other as attachment figures, the combination of twinship and marriage seem to be a challenge for the spouse to be most of all.


Introduction
Twins have a constant companion from the very beginning and they develop close relationships with one another and, as such, it may be a challenge for twins to find a marriage partner who can compete with the co-twin relationship.Thus, the marriage of a twin may not only have an impact on the marital relationship, but also on the co-twin and the spouse to be.Studying the marriages of twins might as well give some more insight of how close and marital relationships are formed and maintained.Earlier studies of marriages of twins are scarce and to our knowledge we have not found any study which has explored the personal experiences of twinship and marriage from a life course perspective.Experiences of married life told by older twins will show how the marriages turned out throughout life, which is the focus of this study.
Twins tend to marry later than non-twins and more twins than singletons remain unmarried according to a large Danish study (Petersen, Martinussen, McGue, Bingley & Christensen, 2011).Possible reasons for this are thought to be related to genetics, as a study by Johnson, McGue, Krueger and Bouchard (2004) showed, that the propensity to marry is heritable and genetically influenced, while the study by Petersen et al (2011) suggested that the reason could be the special relationship that twins share with each other, since twins may feel threatened when the intimacy with the co-twin is broken up.Earlier research has suggested that by marrying someone with a personality similar to their co-twin, twins may want to recreate the twin relationship (Byng-Hall, 1995;Zazzo, 1976).Twin researcher, Nancy Segal, 2000;2011) suggests that if a twin wants to marry someone with a personality similar to their co-twin, a solution might be to marry the sibling or close friend of the co-twin's spouse, but to what extent this happens is unknown.A study by Lykken and Tellegen (1993) showed that twins' choice of marriage partner seemed to be random and based on romantic infatuation.The hypothesis was that the choice of marriage partner among twins is genetically determined; as identical twins who share 100% of their genes would choose partners similar to each another.Their study showed that twins tended to choose similar things in other areas of living, such as friends, clothes, vacations, choices that reflect their genetic and environmental similarity, but not mates.Their study also showed that when identical twins were asked to rate the co-twins' selection, 39% liked the choice of the co-twin, but 38% disliked them and only 5% said they could have fallen themselves for the spouse of the co-twin (Lykken & Tellegen, 1993).
Except for the choice of the marriage partner, other factors contributing to the quality of a marriage among twins can be related to the kind of relationship that twins share.Twin relationships like any other relationships are unique, but some twins have a very close relationship and it is important to distinguish the degree of closeness in twin relationships.A twin relationship can be experienced as close and yet independent, while other twin relationship can be experienced as close, but dependent (Penninkilampi-Kerola, Moilanen, & Kaprio, 2005;Schave & Ciriello, 1983).Dependency between twins may have a negative impact on new close relationships, such as a marriage partner as indicated in a previous study by Pietilä, Björklund and Bülow, (2012).
Studies on the quality of marriage have shown that although marriage quality is only partly genetically determined (Spotts, Neiderhiser, Towers, Hansson, Lichtenstein, Cederblad, Pedersen, & Reiss, 2004;Spotts, Prescott & Kendler, 2006), it is likely that divorce is (Jerskey, Panizzon, Jacobson, Neale, Grant, Schultz, Eisen, Tsuang, & Lyons, 2010;McGue & Lykken, 1992;Trumbetta, Marcowitz, & Gottesman, 2007).Divorce has been considered an objective measurement of marriage quality and the divorce rate among twins according to the study by Petersen et al (2011) showed that female twins have a lower divorce rate than female non-twins, but male twins have the same divorce rate as male non-twins.With the divorce rate in mind the quality in terms of closeness in the marital relationship comes into focus.On the other hand, the nature of twinship, consisting of two individuals having shared their lives from the beginning, could be beneficial for the marital relationship in the sense that twins have developed adaptive and social skills beneficial in their future romantic relationships (Foy, Vernon, & Jang, 2001).If that is the case, research on twins' social lives and relationships might give insight applicable to non-twin relationships as well.Attachment theoretical studies on twins argues that twin relationships are no more special than the relationship of non-twins and that the kind of relationship that twins share with each other instead can be classified as attachment relationships (Tancredy & Fraley, 2006).

Attachment
The theoretical frame for understanding twin relationships and marital relationships in this study is based on attachment theory.The attachment-theoretical model is used as a framework to understand how close and intimate relationships are formed and it is based on the assumption that human beings have a psychological need to connect with each other (Ainsworth, 1989;Bowlby, 1969;1980).This kind of connectedness or 'attachment', in contrast to other kinds of human relationships, is characterized by seeking closeness (proximity seeking), support (safe haven), and security (secure base) when being stressed and becoming anxious when there is a risk of being separated from the attachment person (separation anxiety).These features describe a secure attachment according to Bowlby (1969Bowlby ( ,1980) ) and the person or persons in target as attachment figures.The function of attachment relationships were first observed between infants and their parents (mothers in particular) and depending on the kind of maternal care they received, the infants developed different styles of attachment (Ainsworth, 1989;Bowlby, 1969Bowlby, , 1980)).
Later, the attachment theoretical model extended to include adult romantic relationships (Hazan & Shaver, 1987;Hazan & Diamond, 2000) with the styles of attachment being similar to those of children.In addition to the secure attachment described above, other styles were identified.The anxious-preoccupied style is seen in individuals who seek high levels of intimacy, approval and responsiveness from their partners and tend to be overly dependent on their partners.The dismissive-avoidant style includes those who want a high level of independence and avoid close relationships.Individuals with a fearful-avoidant attachment style have mixed feelings about close relationships, both wanting the closeness of the relationship and feeling uncomfortable with emotional closeness.Adding adult romantic relations to the attachment theoretical model points to the idea that people develop new attachment figures in adulthood -e.g. the spouse replace the parents as primary attachment figure.Thus it is possible to have multiple attachment figures through life, something that has been described as hierarchies of attachment in young adulthood (Trinke & Bartholomew, 1997) as well as over the life course (Doherty & Feeney, 2004) and in old age (Cicirelli, 2004(Cicirelli, , 2010)).According to Cicirelli (ibid.),old people most frequently named adult sons and daughters as attachment figures (for one or more attachments features) while spouse was named most often as full primary attachment (ranked first for all three investigated features: proximity seeking, safe haven and secure base).
According to Tancredy and Fraley (2006), who conducted a systematic study about twin bonds in accordance with the attachment-theoretical model, twins more likely used their co-twin as attachment figures than non-twins considered their siblings as such.Considering dating and marriage, twins seemed to be less likely than non-twins to regard their romantic partner as attachment figures.According to the attachment hierarchy the authors states that "although co-twins were at the top of the attachment hierarchy among twins, they shared that spot with other significant people, such as friends and romantic partners."(p.88).Although with some limitations, the study revealed that the pattern for attachment figures differed for twins and non-twins in old age.Older twins more likely relied upon siblings for "attachment-related functions" than younger twins, while older non-twins "felt less attached to their siblings than younger non-twins."In a recent and larger survey study on a national representative sample, the same authors (Fraley & Tancredy, 2012) report that identical older twins constitute the exception for the common pattern that older married people feel less attached to their siblings, compared to younger married people.Both studies were cross-sectional and questionnaires were used, which has the advantage of quite large number of participants but the disadvantage of lacking elaborated experiences about the life as a twin.
Experiences of the marital relationship in relation to the co-twin relationship told from the perspective of older twins are scarce, and therefore the aim of this study was to explore and describe older twin`s experiences of their marriage in relation to their co-twin relationship.

Method
This study is part of a research project comprising the life stories of older twins, and the study design was qualitative using latent content analysis (Graneheim & Lundman, 2004;Krippendorff, 2004).Personal experiences are context bound and with content analysis it is possible to make replications and valid inferences from data to their context.

Participants
The 34 participants were chosen with the purpose of finding a variety of experiences of twinship and they were also a subsample of two longitudinal studies on older twins; the Swedish Adoption Twin Study of Aging (SATSA) (Lichtenstein, DeFaire, Floderus, Svartengren, Svedberg, & Pedersen, 2002;Pedersen, McClearn, Plomin, Nesselroade, Berg, & DeFaire, 1991) and the Gender study (Hancock-Gold, Malmberg, McClearn, Pedersen, & Berg, 2002).The participants were female/male identical and non-identical twins reared together (n=18) and apart (n=15).Twins reared apart were placed in two groups based on the time when they were separated.In this study, the twins who had been separated directly after birth or in the first year after birth and been placed in foreign adoptive homes, were placed in group one (n=8).Those who had lived their first years together in their biological family and then separated, were placed in group two (n=7).The first group of separated twins had met several years later after separation and had stories to tell about their marriages in relation to their co-twin relationships.The ages of the participants in this study ranged from 70 to 91, the mean age was 81years.Those who married were between 17 and 50 when they first got married.All except one twin pair got married on different dates, ranging from three months to several years.At the time of conducting this study, 15 of the 34 participants were widowed or divorced.

Data Collection
The data in this study consists of 34 interviews and the participants were interviewed once by the first author.To make sure that the participants would feel comfortable and free to tell their stories, they were asked to choose where they wanted to meet the interviewer.All, except two who wanted to meet in a public place, chose to be interviewed in their home environment.
The interviews were audio-taped and transcribed verbatim by the first author.The transcripts include the questions and statements of the interviewer (first author) to show how the interview developed out of the interaction between the participant and interviewer.This study focuses on the parts of the life stories that concern dating and marriage.The questions related to the topic were, for example: As twins, what was it like when you were dating?How did you meet your husband/wife?How did you or your co-twin feel about either one finding a marriage partner?What happened after you got married?
To make sure that the interviews were concluded in good spirits, the final questions focused on something positive, e.g.'what is the nicest memory of your twin relationship?'The participants were asked if they wanted to read through the transcripts to approve their interviews and make it possible to comment on or change something they had said.Those who wanted to read their interviews did so without wanting to make changes and the participants who chose not to read their interviews felt there was too much text to read.

Data Analysis
The purpose of the analysis was to describe variation by identifying commonalities and differences in the text.The interviews were read through several times to get an overview of the content.Thereafter, content or meaning units related to dating and marriage was identified.A meaning unit, according to Graneheim and Lundman (2004), consists of words, sentences or paragraphs containing aspects related to each other through their content and context.Thereafter, the meaning units were condensed, in the sense that the text was shortened, but without reducing the core content of the meaning unit.The condensed meaning unit was then labeled with a code.A code can be assigned to discrete objects, events and other phenomena according to Graneheim and Lundman (2004).The next step was to create categories of the content that shared commonalities.Thereafter the categories were divided into main categories and sub-categories where the main category shows a higher level of abstraction.So far, the analysis comprised the manifest level, which was directly seen in the text.The next step was to identify a pattern of regularity through all of the categories, which would be the latent level, showing the underlying meaning of the text and summarized in a theme (Graneheim & Lundman, 2004).The main categories, sub-categories and the theme are presented in the results section.The analysis was conducted by the first and the third author and interpretation of the categories were discussed until consensus was reached.

Ethical Considerations
This study is approved by the ethical committee at Karolinska Institute, Stockholm (Dnr 84:61, with amendments 97-051, 98-319 and 00-132).The verbal and written information given to the participants included the purpose of the study and that they were being asked to participate to tell their life stories of twinship.They were also informed that the study was voluntary and that they could withdraw at any time without having to explain the reason.Confidentiality was ensured by the change of names and places.

Results
The presentation in the results section is based on the categories identified in the analysis in relation to the purpose of the study, which was to explore and describe older twins' experiences of their marriages in relation to their co-twin relationship.Two main categories, based on the time before and after getting married, emerged in the texts and are presented together with their subcategories.The first main category 'courtship', describes the time before getting married and consists of two subcategories; 'first romantic relationships' and'getting married', describe whom the twins married and what eventually led to marriage.The second main category, 'twinship and the quality of married life', describes experiences of married life after the wedding and in relation to the co-twin relationship and consists of three sub-categories; 'the disharmonious twin/marriage relationships' and the 'harmonious twin/marriage relationships' and the third sub category 'twinship and marriage in later life', The theme running through all categories is labeled 'phases of marriage' and represents the latent level of the content analysis and summarizes the experiences of marriage and twinship.

Courtship
The participants in this study were raised in Sweden in the early 1900s and they grew up both in cities and on the country side.Means of transportation were often limited to bicycles, cars and trains, meaning that young people did not travel to the extent that they do today.At that time, young people often met at their hometown or neighboring town's local meeting places and it was often there that they started to go out with other people or met wives or husbands to be.

First Romantic Relationships
For twins, the courtship days sometimes meant taking advantage of the fact that they looked the same in particular, identical twins could swap boy and girl friends, but often there was a sense of respect and loyalty towards the twin partner not to interfere in his or her relationship.R: (Note 1) -Did you fall in love with the same boys?"P: (Note 2) -No, when we went dancing we never danced with the same boys, that's quite strange but there was one boy who came to our workplace [they both worked for the same company] and she made a date with him, but when she got home she said 'no, I don't want to go!' and I said 'well, I'll go instead' (laughing) and I went out with him several times and finally he said 'Imagine, it's not at all difficult to tell you apart, you're so different!' Yes, he was fooled from the start and he hadn't got a clue!That was quite funny." Dating someone was experienced as something natural when entering adulthood and most twins did not have a problem with their co-twin's dates.Mostly they started dating at the same time.However, any exception to this was related to the kind of relational patterns in the twin relationships.There were twins who had difficult and dependent relationships with one another and for those twins courtship meant competing with the boy/girlfriends, as well as finding it hard to accept that the co-twin had a boy/girlfriend: R:-How did your sister react when you met someone and got married?P: -No, no she rang several times and asked me to come home because things were so awful between her and Mom.

Getting Married
In twin pairs where the co-twin married much later, reasons for late marriage were personal and included drug addiction, traumatic life events, abusive relationships or simply because of being busy with a career and work.R: -How old were you when you got married?"P: -50." (R: "That old, well, I can imagine that it's not that easy to have a relationship when you travel as much as you do?") P: -o, it's not possible, no one wants to sit and wait for you." Most of the spouses married to the twins in this study were not related, but there were twins whose spouses were relatives (brother/sisters) or friends.Wedding dates were often determined by practical reasons, such as getting an apartment or moral reasons, such as the girl becoming pregnant.The twins did not go out with their spouses-to-be for very long as the general consensus concerning long-term relationships and forming a family at that time was that one should marry before setting up house together.

Twinship and Quality of Married Life
In those days the families were often large and the children usually stayed with their parents until they got married and their first own home was the one they created with their spouse.It was also not unusual after the wedding for two or three generations to continue living together.The twin family relationships developed in different ways, in this study described as disharmonious or harmonious twin/marriage relationships.

Disharmonious Twin/Marriage Relationships
The most common reason for disharmony in family relationships was negative influences from the marital relationship on the twin relationship, in the sense that the conflicts originated from the twins' spouses.The spouses in the disharmonious marriages were not related to or did not know each other before marrying.Conflicts were either related to conflicts between the spouses, who did not get along with each other, or caused by the spouses creating competition in the twin relationship by comparing the twins with each other.This, in turn, caused conflicts which, if not resolved, created a distance between the twins.The divorce and remarriage of one twin illustrates the impact of the spouse on the twin relationship: "… My brother is divorced, but there was a time when his ex-wife created competition between us yes, in some way she created a competitive situation that became difficult so we withdrew a little but now he has a new wife and everything is just fine." Not only did the dislike of spouses cause problems, but the opposite could also cause trouble; when a spouse fell in love with the co-twin.Romantic suggestions were rejected out of loyalty and respect for the co-twin.In turn, the spouse who was turned down tried to prevent the twins from seeing each other.
The second common cause of disharmony in family relationships was the dependent twin relationship.All of the participants in this category were identical twins raised together.Among those, there were twins who were dependent and had not separated from each other.The dependent twins held their twin relationship to be equal to their marital relationship, which was threatening to the spouses.This was especially evident in twin relationships where one twin remained single or had been widowed and who interfered in the married life of the co-twin.One twin moved in with her twin sister and interfered in a frustrating way with her twin sister's marriage: "…so she came with us to the maternity hospital, I was about to give birth and the two of them were sitting outside, in some way it was a little sensitive, my job was to give birth… it was hard work for the marriage …it was almost as if it made her angry, she didn't realize that she was in the way… The twins in this category ended up in conflicts of loyalty and had a hard time putting up boundaries between themselves and their twin's partner.One way of dealing with double loyalties was simply to go behind the back of the spouse and call or meet in secret: "… he [the husband] simply became jealous, there was no way of solving it she [the twin sister] wanted to tag along everywhere and wanted to know where I was … she had to be wherever I was … I wasn't allowed to talk to my friends it was supposed to be me and her it was really tough, sometimes I called when my husband wasn't in." Seen over time, the relationships had a pattern of conflict and disagreement which challenged the loyalty of the twins either towards one another or the spouse.In the end, it seemed like these participants chose to be loyal to their spouses rather than to their co-twins.None of these twins divorced their spouses because of the close twin relationship.Over a life course, the conflicts and disagreements were both on-going and temporary and also had to do with personal dislikes.Similarly, the conflicts were related to the way they were or were not resolved.Even though quite a few spoke of the complications of being a twin in relation to being married, there were also those who had harmonious family relationships.

Harmonious Twin/Marriage Relationships
Among those who seemed to have harmonious twin/marriage relations, the spouses were sympathetic and accepting of the twin relationship.Twins married to spouses who were related spent the most time together after the wedding.Twin and family relationships were experienced as 'harmonious' in the sense that all four, the twins and their spouses continued their relationships with each other in a harmonious and satisfying way.This category includes both identical and fraternal twins, some were reared together and some apart.The twins had a supportive relationship with each other without being dependent.When one of them started dating, if they did not start simultaneously, the other twin experienced this as a natural part of life.One of the contributing reasons for continued harmonious family relationships was related to the mindset and acceptance of the spouses towards the twin relationship.P: … well, the two of us didn't go into town to go to the cinema on our own very often, all four of us went.Yes, we went on holiday together and then we got engaged at the same time my husband was always so kind.
(R: -How have your husbands reacted to the twin relationship?)P:-No, it was nothing; they could joke about our [similarity].
There were also participants whose spouses were related or friends, and who had known each other before getting married.Seen over the life course, this turned out to be a good choice as families who were related to each other or spouses who were friends before getting married continued having close relationships as families as long as they stayed married.
"… we are married to two brothers and we've spent a lot of time together, us and our families … an acquaintance said to my mother 'it's good that your daughters married two brothers, they'll always be able to be together…".
However, the same kind of arrangement became complicated when one twin wanted to divorce his spouse who was related to his sister-in-law.The divorce put an end to the marital relationship forever and to the twin relationship for several years."… when my brother got divorced I took my wife and her sister's side, we were always together until he got divorced and that was almost every week."

Twinship and Marriage in Later Life
By now in old age 14of 34 were widowed, 7 of 34 who were married had gone through a divorce and 7 of 34 had started a new romantic relationship.According to their stories, the twins were the ones left behind and the most common cause of divorce was an unfaithful spouse rather than the twin relationship.Marriages that ended in divorce were described as unhappy, but according to the participants in this study, the divorce was not related to the twin relationship.Instead, the relationship with the co-twin served as a source of comfort and support when one of the twins went through a divorce or was widowed.The degree of support was related to the closeness and the quality of the relationship as there were relationships which were supportive, as well as relationships which were difficult or non-supportive.The non-supportive twins were not available to the co-twin to the same extent as the twins in the supportive twin relationships.R: -What was the response of your twin sister when you went through that hardship?P: -well, she did not respond at all, she is rather cold and emotionally distant…it is complicated I have never had her support.
Exceptions were those twins who were dependent on each other, who, in old age, were possibly more dependent on their co-twins.Besides the support of the co-twin, the rest of the family, now with grown up children, was the first choice to turn to most of the time.R: -When your husband died, what significance did your twinship have?P: -I don't know if she [the twin sister] was there more than anyone else, but I had a feeling anyway that I turned more to her when there was something, I am very close to my daughter, she is fantastic and is always there when everything is just too sad, and she'll sort things out but otherwise, it's my sister.

Discussion
The results show that twins' choice of marital partner seems to be based on infatuation, which confirms the earlier study by Lykken and Tellegen (1993) that mate selection among twins seems to be random and based on infatuation.This study showed that from the perspective along the life course it was clear that not all lived together happily ever after.Older twins looking back on their married lives and twin relationships summarized their experiences in what we labelled harmonious and disharmonious marriages.
For those twins that spent much time together and when dating, it seemed like an amusing time.Despite the possibility to fall in love with the same boy or girl, the twins stayed loyal to each other, which can be related to the kind of relationship the twins had.In the study by Pietilä et al. (2012), different twin relationship patterns were identified and in one of these patterns, which was described as complicated and difficult, competition was present as an aspect which was 'draining' on the relationship.Some of the twins in this study who were in this kind of relationship were also competitive as regards their marriage partner, while those twins who were dependent on each other were intruding on the marriage of the co-twin.In contrast to earlier genetic studies, where the choice of partner has been considered either as attributive to the genetic origin of the twins (Jerskey et al., 2010;Spotts et al., 2004) or that twins choose a partner because they want to recreate a marital relationship that resembles the twin relationship (Byng-Hall, 1995), are not supported by this study.Instead, based on the perspective of time and old age, it shows that even if the twins married out of love, twins whose spouses were related to one another or were friends before marriage continued their lives in a way where both families were involved with each other as long as they stayed married.Spouses who were related had already a relationship with one another which meant that probably less time had to be spent in the establishing of the new relationships and a relationship between relatives was more likely to continue even after the wedding.In this way, unaware or not, the twins could continue their twin relationship as well as have a marriage.
The importance of the twin relationship became obvious again in old age and particularly when the marriage of the co-twin broke up either through divorce or through death.In such life situations the presence and support from the co-twin could have had an adaptive function.The comfort and support from family and friends when facing difficult circumstances or events are well documented in bereavement literature (Stroebe, Hansson, Stroebe, & Schut, 2002;Worden, 2002).However the support from the co-twin again seemed to depend on the quality and closeness of the relationship, as those having a draining twin relationship (Pietilä et al, 2012) were not as available as those twins who had a close and nurturing twin relationship.
From the perspective of attachment theory, the result of this study is interesting whether the marriage relationships were characterized as disharmonious or as harmonious from a life course perspective.Considering the probability that twinship also is an attachment relation, and that twins from early age regard each other as an attachment figure next to their parents (Tancredy & Fraley, 2006), a variety of difficulties might arise when starting a new close relationship in adulthood.These difficulties, which might lead to a disharmonious marriage relationship if not solved, could be experienced mutually within the married couple and between the twins, but might also be experienced by one part solely.We are of course aware of that difficulties in marriage relations including twins might have the same kind of reasons as difficulties in all kinds of marriages.However, since twins more likely regard their co-twin as at the top of the attachment hierarchy (Tancredy & Fraley, 2006), a spouse who has no experience of the same kind of close relationship towards another adult, and instead regard his/her wife/husband as his/her attachment figure, asymmetries in the marriage relationship might arise due the twinship relation during the life course.The twinship relation as well as the co-twin of the wife/husband might feel like a rival whom has to be conquered.Correspondingly, when a pair of twins marries another pair of twins, or spouses that are siblings or close friends, the spouses in each married couple will be more equal regarding attachment figures and their expectations for each other might correspond better.
In the present study, the spouses of twins seem to experience the twinship as more problematic than the twins themselves.This can of course be explained by limitations of the study in which only the twins were interviewed and that the analysis only builds on the twins' narratives about the marriage, and since the kind of feelings of rivalry due to the twinship might be unknown for the twins.Further studies that include both parties in married couples including twins are needed to explore this kind of relationship more deeply and from both perspectives.
Nevertheless, that twins seemed to have less problems with the twinship in relation to marriage relationship might indicate that twins from early age have learnt to navigate between an attachment relationship and an individual life, something that many of the spouses had no experience of.

Methodological Considerations
Using life stories, to meet the objective of this study, twins' experiences of marriages in relation to the co-twin relationship, was found to be suitable, as life stories are personal accounts of experiences, representing the perspective of the participants.Also in terms of expected variation of experiences the selection of participants was suitable.To enhance trustworthiness we included the interviewer's questions and comments in the transcript to show how the interview developed out of the interaction between the two.The citations included in the results section will hopefully show if our interpretations were relevant.A critical point in the content analysis was to define exactly what was meant by "marriage" and as this was discussed within the research team, a consensus was reached for a wide definition including the time before getting married and marriage in old age.A limitation is that the participants were interviewed only once and follow-up interviews could have added more depth to the data.However, the data was considered rich enough to give a picture building on for further studies.Since the participants consisted of both intact twin pairs and singles, the answers of the twins in a pair could be used to validate the respective stories.

Conclusions
Living happily ever after was as this study showed true for some, while it was not for others.Closest to happily ever after were those described in the harmonious marriages.By marrying spouses who already knew each other, the twins could both keep the relationship with their co-twin and have a well-functioning marriage.Those who did not live happily ever after described their marriages as disharmonious which were more related to the respective spouses rather than the twin relationship itself and for some the marriage ended up in a divorce.In accordance with attachment theory and how twins are likely to regard each other as an attachment figure, the combination of twinship and marriage seem to be a challenge for the spouse to be most of all.But when the marriage works, the twinship might be a resource rather than a risk to the marital relationship.