The researchers recruited 64 married, heterosexual couples and told half of them to double the frequency of sexual intercourse for 90 days. The other group went about their lives as usual.

In their daily journals, the group that increased the frequency of sex reported a decrease in happiness and sexual pleasure. Both men and women said the “additional intercourse wasn’t much fun.”

Lead researcher George Loewenstein told the New York Times, “It seems that if you’re having sex for a reason other than because you like and want sex,” you may undermine the quality of that sex and your resulting mood.