Infidelity (synonyms include cheating, straying, adultery, being unfaithful, two-timing, or having an affair) is a violation of a couple's emotional and/or sexual exclusivity that commonly results in feelings of anger, sexual jealousy, and rivalry.
What constitutes infidelity depends on expectations within the relationship. In marital relationships, exclusivity is commonly assumed. Infidelity can cause psychological damage, including feelings of rage and betrayal, low sexual and personal confidence, and even post-traumatic stress disorder. People of all genders can experience social consequences if their act of infidelity becomes public, but the form and extent of these consequences can depend on the gender of the unfaithful person.
Incidence
After the Kinsey Reports came out in the early 1950s, findings suggested that historically and cross-culturally, extramarital sex has been a matter of regulation more than sex before marriage. The Kinsey Reports found that around half of men and a quarter of women studied had committed adultery. The Janus Report on Sexual Behavior in America also reported that one-third of married men and a quarter of women have had an extramarital affair.
According to The New York Times, the most consistent data on infidelity comes from the University of Chicago's General Social Survey (GSS). Interviews with people in monogamous relationships since 1972 by the GSS have shown that approximately 12% of men and 7% of women admit to having had an extramarital relationship. Results, however, vary year by year, and also by age-group surveyed. For example, one study conducted by the University of Washington, Seattle, found slightly, or significantly higher, rates of infidelity for populations under 35, or older than 60. In that study, which involved 19,065 people during a 15-year period, rates of infidelity among men were found to have risen from 20% to 28%, and rates for women ranged from 5% to 15%. In more recent nationwide surveys, several researchers found that about twice as many men as women reported having an extramarital affair. A survey conducted in 1990 found that 2.2% of married participants reported having more than one partner during the past year. In general, national surveys conducted in the early 1990s reported that between 15 and 25% of married Americans reported having extramarital affairs. People who had stronger sexual interests, more permissive sexual values, lower subjective satisfaction with their partner, weaker network ties to their partner, and greater sexual opportunities were more likely to be unfaithful. Studies suggest around 30–40% of unmarried relationships and 18–20% of marriages see at least one incident of sexual infidelity.
Rates of infidelity among women are thought to increase with age. In one study, rates were higher in more recent marriages, compared with previous generations. Men were found to be only "somewhat" more likely than women to engage in infidelity, with rates for both sexes becoming increasingly similar. Another study found that the likelihood of women being involved in infidelity reached a peak in the seventh year of their marriage and then declined afterward. For married men, the longer they were in relationships, the less likely they were to engage in infidelity, until the eighteenth year of marriage, at which point the chance of men engaging in infidelity began to increase.
Research on pregnancy and its effects on sexual desire and rates of infidelity conducted in southern Spain indicated that men were more likely to engage in infidelity while their partner was pregnant. It was estimated that 1 in 10 fathers-to-be engaged in infidelity at some point during their partner's pregnancy and suggested that the likelihood of the man engaging in infidelity increases as the woman's pregnancy progresses through its trimesters.
One measure of infidelity is paternal discrepancy, a situation that arises when someone who is presumed to be a child's father is in fact not the biological parent. Frequencies as high as 30% are sometimes assumed in the media, but research by sociologist Michael Gilding traced these overestimates back to an informal remark at a 1972 conference. The detection of paternal discrepancy can occur in the context of medical genetic screening, in genetic family name research, and in immigration testing. Such studies show that paternal discrepancy is, in fact, less than 10% among the sampled African populations, less than 5% among the sampled Native American and Polynesian populations, less than 2% of the sampled Middle Eastern population, and generally 1–2% among European samples.