New York, July 6: In a surprising discovery, a new study reveals that married people in the US over age 55 engage in extramarital sex more often than younger Americans.

Based on analysis of data from the General Social Survey, the researchers found that just 14 per cent of those under age 55 said they had cheated on their spouses as compared with 20 per cent of married Americans over age 55 reporting they have had engaged in extramarital sex.

The General Social Survey has been monitoring trends and constants in attitudes, behaviours, and attributes of Americans since 1972.

While the overall number of Americans who report having sex outside of marriage has held relatively steady at approximately 16 per cent over the past 30 years, that trend has obscured a startling age-related difference, according to the study published by the Institute for Family Studies.

Rates of extramarital sex by age have diverged since 2000, with increased cheating reported by people in their 50s and 60s, said study author Nicholas Wolfinger, Professor at University of Utah.

These numbers are derived from GSS responses to the question, "Have you ever had sex with someone other than your husband or wife while you were married?" Survey respondents have been asked this question in each survey wave since 1991.

Most of these respondents were married between 20 years and 30 years.

But there may be more going on than lengthy marriages and midlife crises, Wolfinger added.

These older Americans also came of age in the wake of the sexual revolution and, over the course of their lifetimes, have had more sex partners compared to younger Americans.

Also, while a majority of Americans continue to disapprove of extramarital sex, attitudes have softened, particularly among older survey respondents, the study said.

The General Social Survey asks respondents about extramarital sex, not explicitly adultery.

This raises the possibility that the data reflect rising participation in polyamory or "ethical nonmonogamy," extramarital relationships conducted with the active permission of one's spouse.

"No matter how many polyamorists there are today, old-fashioned adultery seems to have risen among older Americans," Wolfinger said.

Extramarital sex more among older Americans