“Moving In With Your Boyfriend Can Kill Your Sex Drive” was how Newsweek distilled a 2017 study of more than 11,500 British adults aged 16 to 74. It found that for “women only, lack of interest in sex was higher among those in a relationship of over one year in duration,” and that “women living with a partner were more likely to lack interest in sex than those in other relationship categories.” A 2012 study of 170 men and women aged 18 to 25 who were in relationships of up to nine years similarly found that women’s sexual desire, but not men’s, “was significantly and negatively predicted by relationship duration after controlling for age, relationship satisfaction, and sexual satisfaction.” Two oft-cited German longitudinal studies, published in 2002 and 2006, show female desire dropping dramatically over 90 months, while men’s holds relatively steady. (Tellingly, women who didn’t live with their partners were spared this amusement-park-ride-like drop — perhaps because they were making an end run around overfamiliarity.) And a Finnish seven-year study of more than 2,100 women, published in 2016, revealed that women’s sexual desire varied depending on relationship status: Those in the same relationship over the study period reported less desire, arousal, and satisfaction. Annika Gunst, one of the study’s co-authors, told me that she and her colleagues initially suspected this might be related to having kids. But when the researchers controlled for that variable, it turned out to have no impact.
