If you went to high school before, say, 1980, it’s likely that all the people you knew who graduated and didn’t continue on to college did the same thing. They soon got married. Now that logic has reversed. You’re more likely to see those with college degrees and higher salaries getting married, years after they’ve checked off a long list of adult milestones.

Marriage is no longer the cornerstone that marks the start of adult life. It’s the capstone you achieve after you’ve crossed the finish line--and mainly for those who do cross the finish line. Today, a larger proportion of top-earning Americans (60%) than middle-class Americans (52%) are married.

This is a trend we’ve followed and discussed for many years. (See “More Babies Born to Cohabiting Parents.”) It was a central theme in Charles Murray’s influential book Coming Apart, which characterized marriage as one of the major fault lines dividing the haves and have-nots among whites. Among Americans ages 25 to 34, the median wealth of married couples is four times that of couples who live together but aren’t married.

The desire to marry among young people is still high, but strained finances and the declining share of jobs that pay good wages without a college education have made marriage a far more uncertain bet among working-class Americans. The gender calculus has also changed: As women’s earnings and education have increased, and working-class men’s prospects have decreased, the incentives to marry are no longer what they once were. (See "Millennial Women Just Can't Find Enough Good Men.") The result? As of 2017, living together has outpaced marriage to become the most common living arrangement among Americans with romantic partners. (See “Cohabitation Takes Over Marriage as Most Common Relationship.”)