Beagy Zielinski is a German-born 28-year-old stylist who moved to New York to study fashion in 1995 and stayed. Just before Christmas, she broke up with her blue-collar boyfriend, who repaired Navy ships.

“He was extremely insecure about my career and how successful I am,” Ms. Zielinski said.

An analysis of census data to be released Tuesday by the Pew Research Center found that she and countless women like her are victims of a role reversal that is profoundly affecting the pool of potential marriage partners.

“Men now are increasingly likely to marry wives with more education and income than they have, and the reverse is true for women,” said Paul Fucito, spokesman for the Pew Center. “In recent decades, with the rise of well-paid working wives, the economic gains of marriage have been a greater benefit for men.”

The analysis examines Americans 30 to 44 years old, the first generation in which more women than men have college degrees. Women’s earnings have been increasing faster than men’s since the 1970s.