Recent research suggests that young couples are doing fine, despite the stereotypes. Most single American adults aspire to be married. But for many now, marriage is supposed to be a capstone achievement rather than a cornerstone of young adult life. The “capstone model” says you are supposed to have all your ducks in a row—education, some professional success, and a clear adult identity—before you marry. The median age at first marriage has increased over the past 50 years in the United States—from 23 in 1970 to about 30 in 2021 for men, and from 21 in 1970 to 28 in…