The expectation of sexual fidelity in marriage is nearly universal in our culture. Treas and Giesen (2000), for example, found that 99% of respondents in their national sample expected their spouse to have sex only with them, and 99% assumed that their spouse subscribed to the same creed. Nevertheless, a nontrivial proportion of married adults report having engaged in extramarital sex (EMS). National sample estimates range from 1% to 26%, depending on the particular data source used (Atkins, Baucom, & Jacobson, 2001; Atkins & Kessel, 2008; Blumstein & Schwartz, 1983; Forste & Tanfer, 1996; Treas & Giesen, 2000; Whisman & Snyder, 2007). Not surprisingly, the revelation of infidelity tends to have a devastating impact on the course of a marriage. Atwood and Seifer (1997) reported that affairs are given as a reason for marital separation by 31% of men and 45% of women. Work by Amato and his colleagues found infidelity to be the most commonly reported reason for divorce, as well as the single strongest proximal determinant of divorce in a hazard analysis (Amato & Previti, 2003; Amato & Rogers, 1997). Identifying risk factors for EMS is, therefore, a pressing task for behavioral scientists.
Several studies have taken up that challenge. However, virtually all of them (Previti & Amato, 2004, is a notable exception) are based on a retrospective approach in which married individuals are asked whether they have ever engaged in EMS. The occurrence of EMS is then typically "predicted" using respondent characteristics, including the quality of the current marriage. A common limitation for researchers using this approach is the causal ambiguity that arises with retrospective data (Allen et al., 2005; Atkins et al., 2001; Burdette, Ellison, Sherkat, & Gore, 2007; Treas & Giesen, 2000). Treas and Giesen, for example, pointed out the difficulty in interpreting "effects" of predictors such as sexual interest or permissive sexual values. They noted that EMS might just as well stimulate interest in sex, or lead people to adopt more permissive values that are consistent with their behavior. Studies using the General Social Survey (e.g., Atkins et al., 2001; Atkins & Kessel, 2008; Burdette et al., 2007; Wiederman, 1997) relied on a measure of EMS that asks whether respondents have ever had sex with someone other than their husband or wife while they were married. A negative "effect" of marital happiness on the probability of EMS in this case (Atkins et al., 2001) is especially thorny to interpret. Not only is it possible that current marital happiness is the result of having experienced EMS, but it is not even clear that the EMS took place in the current marriage (acknowledged as a limitation by Atkins et al., 2001).
I seek to address this limitation with this study. Drawing on previous research and theory in the area, I identify a collection of potential influences on the risk of EMS. In place of retrospective data, I utilize a six-wave national panel study of married respondents followed over a 20-year period. At the outset, all respondents indicated that their marriages were free from problems due to EMS. I then model the risk of EMS in a prospective manner using an event history approach. To my knowledge, this is the first study that employs a hazard-model strategy to examine the influences on EMS. Despite the study's other limitations (discussed below), it is hoped that the findings can be triangulated with those from retrospective studies to provide a more comprehensive picture of the etiology of EMS. I begin by reviewing theoretical issues and previous empirical findings.
Theoretical Considerations and Previous Findings
Focus of This Article
EMS encompasses a variety of behaviors. For example, some couples agree to each spouse having sexual relationships with other partners, and participate in organized activities targeted toward that end. This practice is known as "wife swapping," or in more modern parlance, "swinging" (Bartel, 1971). …