Does Unhappiness Come Before or After Infidelity?

Two explanations for the same hurt

People who have been betrayed may find themselves returning to painful questions: Did the problems between us lead to this? If it hadn't been this particular person, would there simply have been someone else?

The Investment Model of Dating Infidelity provides one theoretical account of why relationship difficulties might precede cheating (Drigotas et al., 1999). From this perspective, infidelity can emerge from a relationship that is functioning poorly. Research has found that personal health and relationship well-being may already be deteriorating before an affair, both for the person who cheats and for the partner who is betrayed.

People with lower relationship satisfaction, sexual difficulties, and communication problems tend to be more likely to cheat. Seeking another relationship may be one way they try to manage their distress (Scott et al., 2017). A related hypothesis concerns the betrayed partner: declining personal well-being might make that person less attractive to their partner, who may then seek someone else. These are possible explanations of how difficulties could develop, not reasons to assign responsibility for betrayal to the person betrayed.

Other relationship theories emphasize the opposite direction. They describe stressful events in a couple's life, including infidelity, as central contributors to psychological distress and dissatisfaction with the relationship (Karney & Bradbury, 1995; Lavner & Bradbury, 2010).

For someone who cheats, guilt, damage to their moral self-image, and the pressure of keeping the affair hidden may undermine mental health. Research has linked infidelity with increased psychological distress and depression among those who engage in it (Hall & Fincham, 2009).

For the betrayed partner, infidelity is a serious violation of trust. It can bring anger, diminished self-esteem, and even severe depressive episodes (Whisman, 2016). Nor does an affair necessarily have to be discovered to have serious negative consequences. In this account, declining well-being may be the price of infidelity itself, rather than an alarm that sounds beforehand.

The two explanations raise a question that a single snapshot of a relationship cannot settle: what was changing before the affair, and what changed afterward?

Following well-being over 12 years

The study published in Psychological Science followed a nationally representative sample of 14,216 German adults for 12 years (Stavrova et al., 2023).

The researchers examined people who cheated and people who were betrayed separately. They tracked changes in personal and relationship well-being and compared those trajectories with a control group of couples who had not experienced infidelity. This allowed them to examine whether declines appeared before the event, afterward, or across both periods.

The measures covered relationship satisfaction, life satisfaction, relationship quality, intimacy, admiration, advantage, conflict, and self-esteem. To analyze changes over time before and after infidelity while accounting for the nested structure of the data, the researchers used discontinuous change models (Singer & Willett, 2003).

Four findings help illuminate the relationship between betrayal and well-being.

Well-being was often declining before infidelity

For both those who cheated and those betrayed, most indicators of well-being were already gradually worsening before the infidelity occurred.

For someone who later cheated, that decline might have contributed to the decision to begin an affair. For the betrayed partner, one proposed explanation is that declining personal well-being could reduce attraction within the relationship, prompting the other partner to look elsewhere.

That explanation does not make the betrayal the betrayed partner's fault. A relationship may contain difficulties that deserve attention without making infidelity the responsibility of the person hurt by it. The finding instead suggests that there may have been warning signs worth noticing before the betrayal occurred.

It also complicates the idea that an affair is always the starting point of a couple's unhappiness. In many cases, some deterioration was already underway.

Greater commitment brought a greater aftermath

People who had invested more in their relationship before the event tended to experience a more substantial decline in well-being afterward. This applied both to people who cheated and to those who were betrayed.

The result is consistent with expectancy violation theory, which suggests that highly committed people may react more negatively to infidelity (Burgoon, 1993). Greater commitment may come with higher expectations of the relationship. When those expectations are violated, the disappointment may be correspondingly stronger.

This is a possible explanation for the pattern, rather than a demonstration of what every highly committed person experiences. Still, the finding suggests that the depth of someone's prior investment matters to the aftermath, whichever side of the betrayal they occupy.

Men who cheated experienced more negative changes

Earlier research has described gender differences in infidelity, including findings that men are more likely to cheat and that male infidelity is sometimes judged more justifiable than female infidelity (Fincham & May, 2017).

Against that background, this study found that men who cheated experienced more negative changes than women who cheated. Women who cheated even tended to show a gradual increase in personal well-being afterward.

One possible explanation is that women may be more likely than men to identify dissatisfaction with the relationship as a reason for cheating. An affair might then serve as a wake-up call to their partner, leading to positive changes in that partner's behavior.

That proposed explanation remains tentative. The reported increase concerns the women's personal well-being; it does not establish that an affair reliably improves the relationship.

After separation, the next relationship mattered

The researchers also asked whether the effects of infidelity extended beyond the relationship in which it happened. If a couple separated, would the effects on personal well-being continue, and what would happen when someone entered another relationship?

Among people who separated after experiencing infidelity, those who did not begin a new relationship continued to show declining well-being. Beginning a new relationship, by contrast, was associated with recovery from the hurt.

It is a familiar storyline in movies and television: a new relationship helps someone heal from the previous one. The research demonstrates that a new relationship can help heal that hurt, though this is not a reason to treat another person or relationship purely as a tool for recovery.

Betrayal does not have to mean permanent unhappiness

Taken together, the findings leave room for both directions of the relationship between unhappiness and infidelity. Well-being may already be deteriorating before betrayal, and betrayal itself can bring further pain. The study helps clarify this picture by tracing whether declines in well-being occurred before infidelity, afterward, or across both periods.

Infidelity is closely tied to personal and relationship well-being, but it does not mean happiness is lost for good. As marriage therapist Esther Perel has suggested, an affair is undeniably hurtful and may directly end a relationship. Sometimes, however, a crisis can also open new possibilities within it.

Understanding what may precede betrayal and what may follow it can help couples make sense of their experience. The hope is that honesty, effort, and professional support can make rebuilding a relationship possible, while also helping each person recover a sense of well-being.

On the chessboard of love, unhappiness is a piece quietly slipping into motion. The move toward another choice may be accidental or long contemplated. That moment of departure may be a misplaced response to a deep longing for happiness—a leap away from reality.