New research suggests simply having more of it isn't the key to marital bliss after all.
Pillow with kissy love note
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Good news for those who simply want to slip into the sheets at the end of a long day and get some shut-eye: new research contradicts the long-held notion that couples who have more sex are happier.

In a study conducted by Carnegie Mellon and published in the Journal of Economic Behavior & Organization, researchers argue that simply having more sex doesn’t make people happier. Instead, people who have more sex are likely happier and healthier in the first place. Translation: If you’re unhappy, just having sex probably isn’t going to make you any happier—in fact, the increased frequency may lead to a decline in desire for and enjoyment of sex.

The participants—128 healthy, married individuals (in heterosexual relationships) between the ages of 35 and 65—were randomly assigned to one of two groups: the first group received no instructions on sexual frequency, while the other was asked to double the amount of sex they had per week.

To determine how intimacy frequency affected happiness, the couples completed a survey at the beginning of the study to establish baselines for health, happiness levels, and sexual habits. During the study, participants answered questions regularly to monitor those levels. And, at the end of the study, a final survey was conducted to gauge whether those levels had changed over the three-month period.

Contrary to what prior research suggests, the couples who were asked to have more sex—and did have more sex—actually experienced a small decrease in happiness, and reported lower sexual desire and less enjoyment.

This could be attributed to the fact that couples were asked to have sex, rather than initiating it on their own, researchers say.

"Perhaps couples changed the story they told themselves about why they were having sex, from an activity voluntarily engaged in to one that was part of a research study. If we ran the study again, and could afford to do it, we would try to encourage subjects into initiating more sex in ways that put them in a sexy frame of mind, perhaps with baby-sitting, hotel rooms or Egyptian sheets, rather than directing them to do so," said George Loewenstein, the study's lead investigator and the Herbert A. Simon University Professor of Economics and Psychology in the Dietrich College of Humanities and Social Sciences.

Despite the findings, the study authors believe that most couples do not have enough sex and that regular intimacy does offer its benefits. Some advice? “Instead of focusing on increasing sexual frequency to the levels they experienced at the beginning of a relationship, couples may want to work on creating an environment that sparks their desire and makes the sex that they do have even more fun," said Krishnamurti, a research scientist in CMU's Department of Engineering and Public Policy.