Extramarital sex: prevalence and correlates in a national survey

Journal of Sex Research, Spring, 1997 by Michael W. Wiederman

In the current study, data from a nationally representative sample of 884 men and 1,288 women (1994 General Social Survey, Davis & Smith, 1994) who have ever been married were analyzed with regard to incidence, prevalence, and correlates of extramarital sex (EMS). Men were more likely than women to report ever engaging in EMS (22.7% vs. 11.6%, p [is less than] .00001), yet, after correcting the probability value for multiple tests, the apparent gender difference regarding the proportion of respondents who had EMS during the past year was not statistically significant (4.1% vs. 1.7%, p [is less than].008). Interestingly, there was no gender difference in lifetime incidence among respondents younger than 40 years of age. Except for the oldest cohort, lifetime incidence of EMS increased with age for men, whereas for women there was an apparently curvilinear relationship such that lifetime incidence of EMS was greatest among those 30-50 years of age. Those who have ever been divorced, and those with greater attitudinal acceptance of EMS, had higher incidence of EMS compared to those who have not been divorced and those reporting greater disapproval of EMS. With regard to possible gender differences, men and women who denied ever engaging in EMS did not differ in their attitudes about EMS, just as men and women who reported having experienced EMS did not differ in their attitudes. The results are discussed in relation to previous research and unanswered questions left for further investigation.

In their ground-breaking research, Kinsey and his colleagues found that approximately one third of men and one fifth of women had had extramarital sexual intercourse (see Kinsey, Pomeroy, & Martin, 1948, p. 282; Kinsey, Pomeroy, Martin, & Gebhard, 1953, p. 417). In the three decades following the Kinsey reports, numerous sex surveys were conducted with convenience samples. In general, the results of these subsequent surveys were either congruent with the Kinsey group's findings or revealed a greater incidence of extramarital sex (see Allgeier & Allgeier, 1995; Goettsch, 1994; and Thompson, 1983, for reviews). In his review, Thompson (1983) concluded, "Population parameters for extramarital coitus seem to be at least 50% for married men, and the figure for married women is rapidly approaching the same level" (p. 18).

The convenience samples upon which this conclusion was based were surveyed during the 1970s and early 1980s. How do those earlier rates of extramarital sex (EMS) compare to more recent findings? Several large-scale sexual surveys recently have been conducted using nationally representative samples. Although EMS was not the focus of these surveys, they do contain relevant data. For example, Smith (1991) reported results based on the 1989 General Social Survey (GSS), a survey conducted annually with a representative sample of American adults. Although the survey did not contain a specific question about EMS, Smith ascertained the proportion of married respondents who reported more than 1 sexual partner during the previous 12 months. He found that only 1.5% of married Americans (0.8% of women and 2.1% of men) apparently had had EMS in the past year. These results prompted some to question whether having multiple sex partners may be a "disappearing practice" among married Americans (e.g., see Allgeier & Allgeier, 1995, p. 430).

Billy, Tanfer, Grady, and Klepinger (1993) reported results based on a national sample of men aged 20-39 surveyed during 1991. They found that 4% of currently married men reported more than 1 vaginal intercourse partner during the past year. Forste and Tanfer (1996) reported results based on a national sample of women aged 20-37 surveyed during 1991. They found that 4% of currently married women reported having had EMS at some point.

Leigh, Temple, and Trocki (1993) reported results based on a national sample of adults surveyed in 1990 with regard to number of vaginal and/or anal intercourse partners during the past 30 days, 12 months, and 5 years. Among those respondents who were married during each time period investigated, 1.2% reported more than 1 intercourse partner during the past 30 days, 3.6% more than 1 partner during the past 12 months, and 6.4% multiple partners during the past 5 years. Regardless of the time span, about twice as many men as women reported EMS. Similarly, Choi, Catania, and Dolcini (1994) reported results based on a national sample of adults surveyed in 1990-91. Among currently married respondents, 2.2% reported having more than 1 vaginal and/or anal intercourse partner during the preceding 12 months, with men about twice as likely as women to have had more than 1 partner.

Laumann, Gagnon, Michael, and Michaels (1994) reported results of their national survey and, although not presented by gender, 3.8% of the currently married respondents reported more than 1 sex partner during the past year (see p. 217). These authors also asked about lifetime experience of EMS and found that 24.5% of ever-married men and 15.0% of ever-married women reported having experienced EMS at some point (see p. 216). A problematic issue in the Laumann et al. study, however, was possible contamination of the EMS items, because 21% of respondents were interviewed with a child, spouse, or some other person in the room (see p. 568). Years earlier, Johnson (1970) found that men and women who completed questionnaires about sexual experience in the same room as their spouse were less likely to report EMS experience relative to married men and women who completed the same questionnaire in separate rooms of the house. In the Laumann et al. study, women were more likely than men to have had another person in the room during participation in the interview, and having a mate in the room during the interview may have inhibited reports of multiple sex partners; 5% of respondents interviewed with a spouse or sex partner in the room reported having had more than 1 sex partner in the last year compared to 17% of those interviewed without a partner present (see Laumann et al., 1994, p. 568).