The old adage goes like this: "Happy wife, happy life."

If you believe a new study, it ought to go like this: "Smart wife, happy life."

Today's generation of heterosexual husbands are happier when their wives are better-educated than they are, the study suggests. However, older generations still have better success when the man is more educated.

The new study, which is published in the August edition of the American Sociological Review, draws its conclusions from examining marriages formed between 1950 and 2004 in the United States. It found a gradual move away from specialized gender roles and toward a more equal model of marriage, starting in the 1990s. According to the study, men began to embrace the idea of a better-educated wife at about the same time women began to outnumber men at colleges and universities.

"Marriages in which wives have the educational advantage were once more likely to dissolve, but this association has disappeared in more recent marriage cohorts," writes lead author Christine Schwartz, a professor of sociology at the University of Wisconsin-Madison.

Not only are men less worried about being the better-educated bread-winners, but the rise of the well-educated woman is actually making marriages stronger, the study found. Using data from various family, income, and educational surveys, the study looked at education and divorce rates among thousands of married respondents, and cross-referenced them with the educational differences between partners. Researchers found a steady reversal in the educational gender gap over those years, as men shifted from being less happy to more so in relationships where their wife was more educated. As a result, divorce rates among such couples went down.

Before the 1990s, a couple with a more-educated wife was believed to pose a higher risk of ending in divorce, the paper says. However, after the 1990s, marriages with a more-educated wife actually fared better than relationships wherein the husband held an "educational advantage." Marriages between equally-educated partners have also become more likely to succeed, the paper found.

In the early 2000s, about 50 per cent of newly-married couples shared the same level of education, the study says. Thirty per cent of new marriages involved a wife who was better-educated than her husband, while the reverse was true for 20 per cent of new marriages.

The paper is co-authored by Hongyun Han, a research data analyst at Northwestern University.