Relationship problems tend to start long before a partner cheats

Cheating on a partner can have a severe impact on a relationship. For some, infidelity can mark the end of a relationship altogether, while others spend time rebuilding trust together in couples therapy or through intense communication.

It's clear that infidelity can cause relationship problems. But a new study in Psychological Science suggests that it can also be a symptom of an already declining relationship. The team finds that the wellbeing of a relationship starts to decline in the years before infidelity happens - and, in general, doesn't fully recover.

Participants were German adults taking part in a 12 year longitudinal study about intimate relationships and family dynamics, which started in 2008. Data was collected annually from 12,000 people from three birth cohorts: 1971-73, 1981-83, and 1991-93, and their children, parents, and partners.

Each year, participants reported whether they or their partner had cheated, how satisfied they were in the relationship, and how satisfied they were with their lives in general. They also answered questions about relationship well-being (e.g. how much intimacy and conflict there was in their relationship).

The team identified 609 participants who had been unfaithful, and 338 who had been the victims of infidelity. They then compared these to an equal number of control participants, who were matched on variables like education level, relationship duration, age, and so on.

Both members of the couples who experienced infidelity reported overall lower levels of wellbeing, relationship satisfaction and life satisfaction, and higher levels of relationship conflict, than members of couples who had not been unfaithful. These feelings also shifted with time. After cheating, perpetrators of infidelity experienced lower self-esteem, lower satisfaction in their relationship and feelings of intimacy, and more conflict in their relationship, compared to before they had been unfaithful. Victims of infidelity reported less self-esteem and more relationship conflict after being cheated on, but no other change in wellbeing.

But for both perpetrators and victims of infidelity, wellbeing gradually deteriorated well before cheating actually occurred. Both parties became less satisfied with their relationship, saw their partner as less admirable, and reported increasing conflict in the years before one partner was unfaithful. Perpetrators also reported a decrease in intimacy before the infidelity.

Neither victims nor perpetrators of cheating bounced back to their initial levels of relationship wellbeing after an infidelity. However, there was a gradual increase in satisfaction and decrease in conflict, and both parties also reported an increase in their own life satisfaction and self-esteem after the infidelity.

The team also identified a couple of individual differences that influenced the results. Participants who reported being less committed to the relationship experienced an improvement in relationship well-being following infidelity, while those with a higher level of commitment were more likely to experience a deterioration. This could be because people who are more committed have greater expectations about their relationship, and so are more disappointed and hurt when an infidelity occurs. Men who cheated were also more negatively affected than women who cheated, who in fact tended to experience a gradual increase in personal wellbeing after the infidelity. The team suggests that women, more than men, cheat because of relationship problems, meaning affairs may act as a wakeup call for male partners who change their behaviour accordingly. This, perhaps slightly controversially, suggests that not all of the repercussions of an infidelity are necessarily bad.

So, overall, the results showed that instances of cheating are preceded by a decrease in personal and relationship wellbeing, both in perpetrators and victims. There is some degree of rebound in these measures after an infidelity, but neither party returns to their original levels of well-being.

More work could be done on understanding the mechanism here: do perpetrators cheat because their relationship is declining already, or does interest in someone else mean that less time and energy is spent maintaining a relationship? Future research could also explore how the specific reasons for cheating affect wellbeing and the likelihood that a relationship bounces back. These insights could all help couples deal with the aftermath of infidelity.