ARTICLE When opportunity knocks, who answers? Infidelity, gender, race, and occupational sex composition Christin L. Munsch | Jessica Yorks Department of Sociology, University of Connecticut, Storrs, Connecticut Correspondence Christin L. Munsch, Department of Sociology, University of Connecticut, Storrs, CT. Email: christin.munsch@uconn.edu To date, the prevailing explanation for gender differences in infidelity has been evolutionary. Adaptive pressures lead men to seek sexual variety and, consequently, take advantage of opportunities for extramarital sex more than women. However, an often-overlooked component of the evolutionary perspective is the way in which social con- text influences behavior. Thus, we extend previous theo- retical accounts by examining the ways in which opportunity is facilitated or constrained by experiences of tokenism. The authors find, for White men, who tend to report favorable treatment in female-dominated work, opportunity is positively associated with infidelity. For non-White men, who report poor treatment in female- dominated work, occupational sex composition and infi- delity are negatively associated. For White and non-White women, occupational sex composition is unrelated to infidelity. KEYWORDS gender, infidelity, occupational sex composition, opportunity, race, White male effect 1 | INTRODUCTION Between 20% and 25% of married men, and 10%–15% of married women, report having engaged in extramarital sex at some point during their marriage (Laumann, Gangon, Michael, & Michaels, 1994; Wiederman, 1997). These liaisons can have devastating effects. For example, in the United States, infidelity is strongly linked to divorce (Amato & Previti, 2003) and can trigger anger, depression, and distrust among those whose partners have been unfaithful (Cano & O'Leary, 2000). Conse- quently, scholars have called for researchers to empirically examine the causes and consequences of extramarital sex (e.g., Mark, Janssen, & Milhausen, 2011). Received: 28 September 2017 Revised: 8 August 2018 Accepted: 26 September 2018 DOI: 10.1111/pere.12261 Personal Relationships. 2018;1–15. wileyonlinelibrary.com/journal/pere © 2018 IARR 1