Romantic infidelity is a common yet complex issue that affects relationships across the globe. A new meta-analysis published in Personal Relationships has synthesized data from over 300 studies to explore the true prevalence of infidelity, revealing that it takes many forms—from sexual betrayal to emotional and electronic connections. The findings shed light on the significant gender differences in infidelity patterns and highlight the lack of consistent definitions and measurements in existing research.
Infidelity is a widespread phenomenon that affects romantic relationships across different cultures and social contexts. It often leads to relationship breakdowns and can have a profound impact on the mental and physical health of those involved. However, the research landscape on infidelity is fragmented, with many studies providing conflicting prevalence estimates.
“Prevalence estimates of romantic infidelity often vary significantly between studies. We wanted to assess how much these differences stem from variations in researchers’ operationalizations of ‘infidelity,’ as well as the data collection techniques and sampling methods that they employ,” explained study author Benjamin Warach, a clinical assistant professor of psychiatry and behavioral health at Stony Brook Medicine.
The researchers undertook a systematic review and meta-analysis, meaning they gathered and analyzed a large body of existing research on infidelity to look for overarching trends and patterns. To find relevant studies, they searched databases such as PsycINFO, PubMed, and Web of Science, using terms related to infidelity, such as “extra-marital,” “cheating,” and “affair.”
Out of the thousands of articles identified, 305 met the study’s inclusion criteria. These criteria required that the studies were peer-reviewed, involved human participants, and provided clear data on infidelity rates. The final dataset included 508,241 respondents from 47 countries, making this one of the most comprehensive reviews of infidelity research to date.
The researchers categorized different types of infidelity into three main forms: sexual, emotional, and electronic. Sexual infidelity was defined as any form of sexual activity outside the primary relationship. Emotional infidelity involved forming deep emotional bonds with someone outside the relationship, while electronic infidelity referred to engaging in intimate behaviors online, such as sexting or participating in online relationships.
The researchers then examined how these different forms of infidelity were measured in the studies, whether through anonymous questionnaires, interviews, or other data collection methods. They also considered demographic factors such as gender, age, relationship status, and nationality to see how these variables influenced the results.
The meta-analysis revealed significant differences in the prevalence of different types of infidelity. Sexual infidelity remains the most studied form (making up over 58% of the studies), with around 25% of men and 14% of women admitting to sexual unfaithfulness.
However, emotional and electronic infidelity, although less studied, were shown to be prevalent as well. About 35% of men and 30% of women reported being emotionally unfaithful, forming intimate emotional connections outside their romantic relationships. Electronic infidelity, which includes behaviors like online flirting or engaging in sexual conversations over the internet, was reported by 23% of men and 14% of women.
One of the key findings of the study is that nonsexual forms of infidelity, such as emotional and electronic betrayal, are underexplored in the research literature. Despite their potential to harm relationships, most studies tend to focus on sexual infidelity. Emotional infidelity accounted for only 9.5% of the studies, while electronic infidelity was featured in just 5.6% of the research.
The researchers argue that emotional and electronic infidelity can be just as damaging, if not more so, depending on the relational dynamics. For instance, many people might feel more betrayed by an emotional connection than a one-time sexual encounter. The rise of digital communication has also created new opportunities for infidelity, yet research has not fully kept up with these technological changes.
The findings also highlighted that many studies used vague or inconsistent definitions for infidelity, which could skew the results. “We found that authors operationalize and/or report romantic infidelity prevalence using behaviorally unclear terms (e.g., ‘cheated’ or ‘been unfaithful’) in approximately 30% of studies; research has previously shown that individuals have widely varying perceptions of what these terms mean. This is a major problem for our research field,” Warach told PsyPost.
Interestingly, the methods researchers used to collect data on infidelity appeared to have an impact on the results. When infidelity data was collected anonymously, participants were more likely to report engaging in sexual infidelity compared to non-anonymous methods, such as in-person or telephone interviews. This suggests that people are more comfortable disclosing sensitive behaviors like infidelity when their identity is protected.
The discrepancy was especially clear with sexual infidelity, but this effect was not observed with emotional infidelity, which might be less stigmatized than sexual infidelity, making people more willing to admit it in both anonymous and non-anonymous settings.
As for sampling methods, the researchers observed that convenience sampling—where participants are selected based on availability rather than being randomly chosen—resulted in higher reported rates of infidelity compared to studies that used more representative, randomized sampling methods that aim to reflect the broader population. This is likely because participants in convenience samples tend to self-select into studies, often bringing more liberal attitudes toward relationships or higher levels of sexual experience.
The researchers suggest that the field of infidelity research should aim to develop clearer, more consistent definitions of what constitutes infidelity. Without a shared understanding, comparing results across studies remains challenging, and this limits the applicability of research findings to real-world relationship issues.
“Our study shows that inconsistent definitions and measurement methods contribute to confusion about romantic infidelity prevalence in the research literature,” Warach said. “For the average person, this underscores the importance of clear communication in romantic relationships about boundaries and exclusivity expectations – what one person considers ‘infidelity’ might differ from their partner’s understanding.”
The study, “The current state of affairs in infidelity research: A systematic review and meta-analysis of romantic infidelity prevalence and its moderators,” was authored by Benjamin Warach, Robert F. Bornstein, Bernard S. Gorman, and Anne Moyer.
