Extra-dyadic emotional closeness as a third type of 'infidelity': expectations, emotional responses and individual differences

When relationship partners act in ways that violate our expectations and trust, we can feel betrayed and experience intense emotional distress and confusion. In two studies, drawing on both undergraduate student and community samples and using anonymous self-report questionnaires, this thesis explored beliefs about what constitutes infidelity, one of the most common and psychologically damaging forms of romantic betrayal. In Study One (N = 272) respondents were asked to specify which extra-dyadic behaviours would breach romantic relationship trust. Findings confirmed the idiosyncratic nature of expectations for romantic exclusivity, and suggested that for many individuals relationship trust would be damaged if a partner engaged in emotionally close interactions such as confiding, sharing time and seeking another for emotional support. -- Based on evolutionary research into the emotion of jealousy, Study Two (N = 226) investigated a three component model of extra-dyadic partner involvement: sexual, emotionally close, or love. Overall, both males and females reported that emotionally close extra-dyadic involvements had the potential to elicit distress, although this distress was generally expected to be less than that caused by extra-dyadic sex or love involvements. In its investigation of emotionally close extra-dyadic partner involvements as a third type of 'infidelity', these two studies have made some progress in mapping the territory of distress represented by different types of extra-dyadic intimacy. These initial findings suggest that being female, young, or having an anxious attachment style, and/or high levels of trait jealousy may increase the risk of emotional distress in response to partner extra-dyadic emotional closeness with another, while high levels of relationship commitment may be a protective factor. These individual characteristics may be important aspects of both clinical assessment and treatment in therapy for couples trying to mend relationships after events construed as betrayals.