Perhaps the most common, and complex, domain of human behaviour leading to relationship upset would be the expression of an individual’s sexuality and gender roles. In the vast majority of cases this is inherently relational, personal, private and intimate. The extra-marital affair is usually the most disruptive cause of relationship conflict and eventual separation, yet many survive such affairs and go on to evolve improved relationships – if the work is done, hard yards in the long haul!

Sexuality is perhaps one of the most difficult areas of human behaviour to gain accurate information. No other topic produces more lies and deceptions. Yet it is also one of the most profound and rewarding experiences considered by most to be a necessary component of their most intimate relationships. Gender can be defined as the culturally sanctioned ways of expressing one’s genetic sex, and tends to have strong prescriptions and prohibitions based on cultural stereotypes.

Human sexuality is also known to encompass a wide variety of practices accepted among consenting adults. A much narrower range of sexual behaviours tend to be approved at a social level, with those falling outside this range considered deviant. But by whose standards is normal sexuality defined? Legal sanctions tend to limit sexual expression to safer versions, excluding minors and non-consenting adults.

Widespread expectations exist for sexual expression within certain relationship styles, for example, monogamy is usually implicitly understood to be the basis of marriage, hence affairs are often cited as the cause of marital dissolution. Yet many relational forms are practised in private among consenting adults, sometimes in community sub-cultures, sometimes evolving among particular participants, usually out of view of those dominant cultural groups that voice disapproval.

Given that sexual relationships tend to be among the most intimate we experience, we also find the strongest emotions aroused by sexual practises inconsistent with our own favoured versions. Both homicide and suicide are most common in disrupted sexual relationships, so exploration in the sexual domain requires safety be considered paramount. Given longstanding cultural, legal and moral limitations on open sexual expression, honest exploration and understanding requires considerable time for trust to be earned, tolerance developed, and perhaps acceptance of difference – at least for consenting adults.

Given that illicit/deceptive affairs usually result in relationship conflict, if not separation, why do some survive, even thrive, following the discovery of an affair? Partners to a relationship usually undertake major reassessments of their place and roles following discovery of an affair. Many decide to terminate the relationship, trust forever lost and betrayal intolerably humiliating. Those that decide to remain must adapt and evolve new relationship forms that can accommodate such a major upheaval.