The science of infidelity: The key psychological and contextual factors that predict cheating

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A new review paper in the Journal of Sexual Medicine has analyzed existing research to identify characteristics that influence the likelihood of individuals cheating on their partners. Some of these are individual characteristics (e.g. dark personality traits), while others have to do with the characteristics of the relationship (e.g. commitment). For infidelity to happen, there must also be an opportunity (e.g., an attractive alternative partner available).

Infidelity is the act of being unfaithful or disloyal to a romantic or sexual partner. It typically involves a breach of trust by engaging in a relationship or sexual activity with someone other than the primary romantic partner (i.e., wife/husband or girlfriend/boyfriend). Infidelity severely damages the trust and emotional bond between partners, leading to feelings of betrayal, hurt, and insecurity. In this way, infidelity destabilizes relationships and families, resulting in emotional distress, conflict, and, in many cases, the dissolution of the relationship.

The impact of infidelity extends beyond the immediate relationship. Individuals affected by infidelity often experience intense emotional pain, depression, anxiety, and a loss of self-esteem. The ripple effects can also impact children and other family members, creating widespread emotional turmoil. Legal consequences, such as divorce or custody battles, further complicate the lives of those involved. Long-term effects may include difficulties in forming new relationships and persistent trust issues.

Study authors Charlene F. Belu and Lucia F. O’Sullivan reviewed the existing scientific literature to identify characteristics that make individuals and couples more or less prone to infidelity. They note that because infidelity is so frequent and the consequences of infidelity often so costly, many researchers have worked on identifying factors that can predict whether a person or a couple will experience or engage in infidelity.

The researchers categorized these predictive factors into three groups: individual characteristics, relationship characteristics, and contextual factors. Individual predictors include personal traits that make someone more or less likely to cheat. Relationship predictors involve the dynamics within the romantic relationship. Contextual factors refer to opportunities for infidelity to occur.

In terms of individual characteristics, studies consistently show that individuals low in conscientiousness are more likely to cheat. This tendency increases if their partner also has low conscientiousness. Such individuals often display disorganization, carelessness, and a lack of goal orientation, resulting in unreliability and persistence issues.

Individuals low in agreeableness and high in extraversion are also more prone to infidelity. Women high in neuroticism, as well as individuals with pronounced dark personality traits—Machiavellianism, narcissism, and psychopathy—are more likely to be unfaithful. Women with high attachment anxiety are more prone to infidelity, whereas avoidantly attached individuals are less likely to cheat. A higher willingness to engage in casual sex also increases the likelihood of infidelity. While men historically admit to infidelity more often, this gender gap appears to be narrowing.

Individuals in relationships of better quality and those with higher commitment to their partner are less likely to engage in infidelity. On the other hand, those dissatisfied with their relationship and individuals experiencing sexual dissatisfaction are more likely to be unfaithful. Relationship dissatisfaction is particularly likely to drive women to infidelity, while sexual dissatisfaction is more strongly associated with infidelity in men. That said, even couples reporting high quality of their relationships are at a non-zero risk of infidelity.

Finally, for infidelity to occur, an opportunity must be present. The availability of an attractive alternative partner is a crucial contextual factor. Adults in exclusive romantic relationships often have a crush on someone who is not their partner. However, having a crush most often does not lead to infidelity. For a crush to lead to infidelity, this attraction needs to be communicated in some form and reciprocated by the other individual. Only then does the opportunity for infidelity exist.

Infidelity risk is particularly high for individuals working in environments that contain many potential partners. When an individual spends a long time in such places (e.g., at work), there are many opportunities for infidelity to happen. If one’s social environment does not provide opportunities for meeting or communicating with potential partners, the likelihood of infidelity happening is much lower.

“Given the high cost of infidelity for individuals and relationships and the potential collateral damage beyond, research predicting infidelity has valuable implications for relationships and professionals who are working with partners in distress, Blue and O’Sullivan concluded. “Although individual characteristics are often investigated, relationship factors tend to be stronger predictors of infidelity. Research is needed that explores the sequence of interactions leading to infidelity and important contexts and exchanges with an attractive alternative.”

The review provides a valuable overview of factors associated with risk of infidelity. However, it should be noted that all of the reported factors are just based on statistical associations. A person may exhibit many traits linked to infidelity and still remain faithful, while others may lack these traits and still cheat.

The paper, “Predictors of infidelity among couples,” was authored by Charlene F. Belu and Lucia F. O’Sullivan.