Kevin, a 24-year-old recent college graduate from Denver, wants to get married someday and is “almost 100% positive” that he will. But not soon, he says, “because I am not done being stupid yet. I still want to go out and have sex with a million girls.” He believes that he’s figured out how to do that:

“Girls are easier to mislead than guys just by lying or just not really caring. If you know what girls want, then you know you should not give that to them until the proper time. If you do that strategically, then you can really have anything you want…whether it’s a relationship, sex, or whatever. You have the control.”

Kevin (not his real name) was one of 100 men and women, from a cross-section of American communities, that my team and I interviewed five years ago as we sought to understand how adults in their 20s and early 30s think about their relationships. He sounds like a jerk. But it’s hard to convince him that his strategy won’t work—because it has, for him and countless other men.

Marriage in the U.S. is in open retreat. As recently as 2000, married 25- to 34-year-olds outnumbered their never-married peers by a margin of 55% to 34%, according to the U.S. Census Bureau. By 2015, the most recent year for which data are available, those estimates had almost reversed, with never-marrieds outnumbering marrieds by 53% to 40%. Young Americans have quickly become wary of marriage.

Many economists and sociologists argue that this flight from marriage is about men’s low wages. If they were higher, the argument goes, young men would have the confidence to marry. But recent research doesn’t support this view. A May 2017 study from the National Bureau of Economic Research, focusing on regions enriched by the fracking boom, found that increased wages in those places did nothing to boost marriage rates.