Couples where the husband earned at least $38,000 more per year than his wife were the least likely to divorce. That finding isn’t all that surprising when you consider how men and women tend to rank their preferences in romantic partners. David Buss and others have shown that while both sexes value kindness most highly, their preferences begin to diverge further down the list. On average, men place more emphasis on physical attractiveness, while women place more emphasis on ambition, resourcefulness, and income. So the fact that marriages are most stable when the husband earns significantly more than the wife aligns with those longstanding preferences. It also connects with something I’ve mentioned before. The people who most strongly endorse progressive, gender-egalitarian values tend to be college-educated, upper or upper-middle-class professionals. But when you look at how they actually live, many of them follow a traditional model: the man earns a high income, and the woman either works part-time or not at all. In other words, the couples who talk the most about equality are often the ones whose lives resemble a 1950s family structure the most.