vice.com
A growing body of research suggests that keeping sex exciting is an issue for women, especially in a years-long relationship. Contrary to what the distracted boyfriend meme might have you believe, women grow disinterested in sex with a long-term sexual partner faster than men, and report lower sexual satisfaction.
Women have less interest in sex when they have been in together for more than a year, and women who live with their partner tend to feel less sexual desire than women who don't. Another study published in 2012tells us that the longer a relationship lasts, the more women's sexual desire decreases, which is not the case for men. And finally, the results of a 2006 German study show that while 60 percent of women want to have "frequent" sex at the beginning of a relationship, in the four years that follow this figure drops to less than 50 percent, and after 20 years of relationship, it falls to about 20 percent. The libido of men, on the other hand, generally remains stable throughout the duration of a relationship.
"Women have a tendency to get bored faster than men in a monogamous relationship," Renaud said. "They want a form of sexual variety, while men are often content with very little. It is often women who will lose their desire first, and sometimes even quickly enough."