Some men have more fundamental issues. One 38-year-old Italian manager complained that her boyfriend suggested she change jobs because he no longer felt able to “seduce her” after her salary rose above his. A French management consultant said her husband, a teacher, stopped coming to parties with her because he felt inadequate every time anyone asked him what he did. A German banker said one reason her ex-husband left her for a physiotherapist was “because she would have more time for him.”

“It is amazing how even many liberal-minded men end up having sexual and emotional difficulties being with more obviously successful women,” said Sasha Havlicek, the 35-year-old chief executive of a London research group. A high-flying friend of hers resorted to ritually feigning helplessness with her partner to promote his sense of masculinity. “The male ego can be a more fragile thing than the female ego, which is used to a regular battering and has hence developed a sense of humor!”

Anke Domscheit-Berg of Microsoft Germany, who has stories of past would-be boyfriends fleeing after seeing “director” (of government relations) on her business card, put it this way: “Success is not sexy.”

Dating sites seem to suggest that highly educated women have more trouble finding a partner than women in more traditionally female jobs. “Care and social professions work well; the really educated profiles are more difficult,” said Gesine Haag, 43, who used to run match.com in Germany. An elite dating portal at the company, trying to match up highly educated men and women, was abandoned and refocused more broadly, said Ms. Haag, who now manages her own Internet marketing agency.

“Men don’t want successful women, men want to be admired,” she said. “It’s important to them that the woman is full of energy at night and not playing with her BlackBerry in bed.”

Bernard Prieur, a psychoanalyst and author of “Money in Couples,” says men who earn less than their partners struggle with two insecurities: “They feel socially and personally vulnerable. Socially, they go against millennia of beliefs and stereotypes that see them as the breadwinner. And the success of their partner also often gives them a feeling of personal failure,” Mr. Prieur said in the November issue of the French magazine Marie-Claire.

So are ambitious women condemned to singledom? Or are things changing as the number of female high achievers inches higher?