Macho guys fare worse in relationships where the woman makes more money, according to a new study published in the journal Sex Roles. While this isn't so surprising, what is surprising is that female breadwinners are quickly becoming the norm. In fact, 40 percent of working wives now out-earn their husbands, reveals the latest Bureau of Labor Statistics, and that’s changing the dynamics of female-male relationships, according to the newly-released book The Richer Sex: How the New Majority of Female Breadwinners is Transforming Sex, Love and Family

While this is bad news for macho types, it's a welcome change for guys who don't mind having a sugar mama—and who won't be complaining when their wife offers to pick up the dinner bill. Book author Liza Mundy says that one reason for the gender shift is that men may be a lot more willing to make changes to help women’s careers than they might have been in previous generations, such as putting women through college or moving for a partner’s job. Here are Mundy’s predictions about the gender role shifts that are being ushered in by the trend of women making more money than their partners.

Women will want more sex. A woman who pays the bills and initiates sex? That's what we call a win-win. “Marriage dynamics are complicated, but the interviews I did while researching the book suggest that women feel empowered by their earning power, and this can lead to wanting more sex,” says Mundy. “However, if their partner feels emasculated by earning less than their wife and she feels she can’t talk about her job success at home, then intimacy and their sex life will suffer.” 

Guys will be making like Jamie Oliver in the kitchen. “The kitchen is the new garage, as one celebrity chef put it,” says Mundy. “Men are becoming much more domesticated.” Indeed, the number of hours men spend cooking is rising as it drops for women. Mundy predicts that men will continue to play a bigger part in the housework as women spend more time in the work world.

Mr. Mom will become closer to the norm. Hail the rise of the super dad: While 74 percent of men in 1977 said that women should raise the kids and men should bring home the bacon, only 40 percent think so today. “Statistics show that fathers want to and are spending more time with their kids than previous generations,” says Mundy. “As more women become the primary breadwinners and spend more time at the office, they’ll have to become comfortable with the fact that their husbands may be the ones who all the teachers know at the school’s open house.”

Men will get in touch with their metrosexual side. “There is this idea that marriage is kind of a trade, where men traditionally bring earnings and women bring beauty or services such as sex or housekeeping,” says Mundy. However, especially in cities such as Atlanta where more and more women out earn men, women are less willing to alter their appearance per a mate’s request (such as changing their hair or losing weight), while they’re more likely to have high expectations about their partner’s attractiveness. Earnings alone may no longer be enough for a man to attract a mate, and men are increasingly going to bring good looks into a relationship, says Mundy. We're not sure if we buy it, but it couldn't hurt to do a little manscaping.

Good listeners will get the girl. “One study found that, while female breadwinners were grateful for their husbands’ housework, what they valued most was supportive listening,” says Mundy. Translation: Doing the dishes will score you brownie points, but the real way to a woman's heart may be lending a sympathetic ear—and you probably won't even have to buy her dinner.