"Someone told me the delightful story of the crusader who put a chastity belt on his wife and gave the key to his best friend for safekeeping, in case of his death. He had ridden only a few miles away when his friend, riding hard, caught up with him, saying 'You gave me the wrong key!'"
Rates and Demographics of Infidelity
In the late 40's and early 50's when Alfred Kinsey was compiling his data for what would later be called the Kinsey Reports, he estimated that approximately 50% of all men and 26% of women would, at some point in their married lives, engage in extramarital activity (Kinsey, et al. 1948; 1953). Further studies have bounced between confirming and disputing that claim. More recent studies point to lower percentages, especially for the male population. Whether trends have changed over the past 60 years, something entirely possible, or whether Kinsey's data was incorrect at the time, is only a guess. Current studies report infidelity at a rate of 23-34% for men and 15-25% for women (Wiederman, 1997; Mark, Janssen, Milhausen, 2011), significantly below the Kinsey figures.
Infidelity in Heterosexual Couples examined a multitude of factors, including pre-relationship and in-relationship sexual behavior, to determine what types of behavior might have an impact on extramarital promiscuity. Among their many findings pertaining to sexual activity:
• Individuals reporting infidelity also reported significantly higher rates of one-night stands (mean rates of 6.3 vs 3.5).
• Individuals who engaged in anal intercourse once or more over the past 6 months were more likely, although not significantly more likely, to have engaged in infidelity.
• There were no significant differences between those who had engaged in extramarital activities and those who had not in terms of the amount of sexual activity, masturbation frequency, and vaginal intercourse frequency.
• Men and women who engaged in regretful sexual behavior in negative or positive mood states have higher rates of infidelity.
Also examined were many standard demographics such as gender, race, importance of religion (but not type of religion), marital status, education, income and employment status. In regards to gender, Infidelity in Heterosexual Couples found that 23% of males and 19% of females in the study self-identified as having engaged in extramarital activity in their current relationship (and all participants were in relationships at the time of the study). Marital status emerged as a better identifier of infidelity, in this study, with unmarried couples and cohabitating couples reporting extradyadic activity 8% less often, irrespective of gender, than their married or separated/divorced/widowed counterparts. Other studies have found opposite results.
Race was not indicative of infidelity by the results of this study - the spread between the lowest racial classification and the highest was only 1.3%. Income and employment status showed that full time employees in upper middle income brackets are more likely to engage in infidelity than their poverty level or unemployed counterparts. By contrast, however, the education level worked in reverse. Those with only a high school education were significantly more likely to have sex outside of their relationship than their peers who were either still in post-secondary school or had graduated by 7-11%. Importance of religion was another successful predictor of infidelity with only 10.7% of people who self-identified religion as being 'Very Important' to them also reporting infidelity. Rates of infidelity jumped significantly beyond this point, with those rating religion as 'Important' reporting infidelity at a rate of 19.6%, 'Slightly Important' at a rate of 21.9%, and 'Not Important' at the highest rate of 26%.
So what does it all mean? Certain demographics suggest infidelity, but by no means are they an assured method of predicting extradyadic activity. Despite some demographic trends, the researchers found that "for both men and women, sexual personality characteristics and, for women, relationship factors are more relevant to the prediction of sexual infidelity than demographic variables such as marital status and religiosity" (Mark, Janssen, Milhausen, 2011). In layman's terms - personality and causation are higher predictors of infidelity than demographics.
Personality and Causation: the 'why' of infidelity
While there are a myriad of factors that influence infidelity, there are a few factors commonly believed to impact the decision to cheat that have little to no impact on infidelity. Chief among these mistaken beliefs is frequency. Infidelity in Heterosexual Couples polled participants on their general frequency of sexual activity inside the relationship. Greater than 80% of the respondents reported engaging in some type of sexual activity with their partner at a rate of weekly or greater (several times a month, once or twice a week, or several times a week) - yet more than a fifth (22%) of all participants have engaged in extradyadic activity, many of whom answered that they frequently engaged in sexual activity with their partner.
Another incorrect assumption is that low premarital sexual satisfaction is a predicator of infidelity. Premarital Precursors to Marital Infidelity (Allen, et al., 2008) found that lower premarital sexual satisfaction was an indicator in males, but not in female. Female infidelity was "characterized by significantly higher female sexual satisfaction, premarriage." And finally, the idea that premarital satisfaction and communication can definitively predicate infidelity is false. As noted in Premarital Precursors to Marital Infidelity, couples who experienced infidelity had high relationship adjustment scores and a higher rate of positive communication than negative communication; furthermore "although there are differences that are detectable statistically, by and large couples who go on to experience infidelity do not appear uniformly distressed and hostile with one another premaritally."
More important than the variables that are mistakenly assumed to relate to infidelity are the variables that do predicate higher rates of extradyadic activity. Inhibition and excitability, communication, and relationship satisfaction are all units commonly measured to predict possible infidelity. Easiest to measure among these variables are the SIS1/SES/SIS2 scores that have become a common part of psycho-sexual research.
SIS1, or the Threat of Performance Failure, refers to an individual's sexual inhibitions, such as ability to maintain arousal if caught having outdoor sex, while the SES measures sexual excitation, or propensity to arousal. The SIS2 scale, known as the Threat of Performance Consequences, measures the inhibition of the individual with regard to consequential behaviors such as non-safe sex with a risk of pregnancy or STI transmission. In and of themselves, these tests do not measure rates of infidelity, however, their scores are playing a large part in determining predicators to sexual unfaithfulness. **If you are interested in seeing your own SIS/SES scores, visit the Kinsey Institutes' website or click here.**
Both men and women who engaged in infidelity score higher on the SIS1 and SES tests and lower on the SIS2 scale than their counterparts (Mark, Janssen, Milhausen, 2011). High SES/SIS1 and low SIS2 scores have been linked to impulsivity and high-risk behavior in multiple studies, including The Effects of Impulsivity, Sexual Arousability, and Abstract Intellectual Ability on Men's and Women's Go/No-Go Task Performance. This is further correlated by the finding in Infidelity in Heterosexual Couples that individuals that engaged in infidelity reported significantly more one-night stands, an established high-risk behavior.
Communication, long known to be one of the most important parts of a relationship, has also shown to contribute to infidelity. Relationships characterized by high levels of one-sided negative communication are especially susceptible to extradyadic activity, more so when high levels of invalidation occurred (Allen, et al.). Most interestingly, while Premarital Precursors employed a standard comparison to detect infidelity probability, they also used a controlled comparison to detect correlation, and in all instances but one the controlled comparison negated the predictor. The single anomaly was female invalidation - even when accounting for male correlation, female invalidation continued to be a successful predictor of infidelity for men.
The final measure of causation is relationship satisfaction. Infidelity in Heterosexual Couples used 3 variables to examine relationship satisfaction: happiness, sexual satisfaction, and perceived compatibility. In all variables, for both men and men, those reporting extradyadic activity expressed higher dissatisfaction rates than their counterparts. Chief among these variables for sheer percentage volume was perceived incompatibility - 53% of women and 74% of men who had engaged in infidelity rated themselves incompatible or very incompatible. However, in the group that did not report infidelity, more than half still rated their relationships as incompatible or very incompatible. What does this tell us? In addition to displaying the high propensity of individuals to enter into relationships and remain in them with those they feel incompatible with, this data shows us that controlled correlations are of greater scientific value than bare comparisons. Taking controlled values into account, women's highest predicator of infidelity is unhappiness, with no second value of high accuracy; men's is unhappiness as well, but with sexual satisfaction a near second. Allen, et al. also found a similar relationship between infidelity and relationship satisfaction, although the value, when measured in couples, is highly correlative.
Now that we have tons of numbers and data, what does it all mean? Can we predict sexual infidelity?
Yes and no. We know, especially in men, that certain variables suggest a propensity for infidelity, but they are by no means a guarantee. Women, on the other hand, do not appear to follow highly predictable paths to infidelity, but some indicators do exist. However, just because your spouse or significant other falls into one of these categories does not mean they will cheat (Mark, Janssen, Milhausen, 2011).
More and more studies are proving that infidelity is not usually a one-way street. Rarely is one person in a relationship engaging in infidelity while the relationship is highly satisfying to both partners. Nor do we often see a situation where one partner is extremely unhappy and the other highly satisfied. Happiness and satisfaction are correlative: the measure of one person's value is highly related to the measure of the other persons value. A woman who nags does not drive her husband to infidelity any more than a man who fails to perform adequately in the bedroom drives his wife to cheat. Due to the high instance of overlap between behaviors and their correlative values, one cannot simply say this person or that person is going to cheat. Instead of attempting to predict individual or gender based precursors, we should focus on the relationship as a whole. Certain patterns seem to predicate infidelity, low relationship satisfaction, poor positive communication, high negative communication, perceived incompatibility, and high emotional invalidation, but we should see these values as indicators of overall risk for the couple and possible reception to extradyadic relationships rather than measuring them as definitive individual identifiers (Allen, et al).