“Blue” marriages are better — or at least that is the conventional wisdom. Couples who live according to egalitarian values, sharing domestic responsibilities like housework and cooking, have long been seen as superior by most academics, journalists and public intellectuals engaged in the national conversation about the American family.

“We have every reason to believe that new values about marriage and sex roles will make it easier for parents to sustain and enrich their relationships,” the feminist family historian Stephanie Coontz wrote in 1997 in “The Way We Really Are: Coming to Terms With America’s Changing Families.” At the end of the last century, Ms. Coontz believed, the arc of American family life was bending toward a better and brighter future — a progressive one.

Today, this view retains considerable currency. A 2016 report from the Council on Contemporary Families suggested that in “today’s social climate, relationship quality and stability are generally highest” in more egalitarian relationships. The Bloomberg Opinion columnist Noah Smith has speculated that “maybe liberal morality is simply better adapted for creating stable two-parent families in a post-industrialized world.”

But consider Anna and Greg, a couple that one of us (Mr. Wilcox) recently interviewed for a book on marriage. When Anna started having children, she had no wish to work full time outside the home. Anna is not alone in this regard: The Pew Research Center reported in 2013 that about two-thirds of married mothers would prefer not to work full time — a fact that is often overlooked in our public conversation about work and family, which is heavily influenced by progressive assumptions. Anna says she is grateful that because Greg works hard at his small business, she has been able to make this choice.