‘This Was The Biggest Mistake I Made When I Moved In With My Boyfriend’

The issue: At 34, Shelly bought her first home on her own. When her then-boyfriend of a year moved in, they split the monthly mortgage and utility payments. “But then another side of Mike emerged. He had to have everything his way, and he started tackling home improvements—things I hadn’t asked him to do. He installed a hot tub and built a shed in the backyard.” When they broke up after two years, he said she owed him $15,000 for what he put into the house. “We’re still fighting about it! Now he’s pissed if I even take a vacation because he says I should be paying him back.”

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Why it happens: About 10 percent of unmarried men and women—or more than 7 million people—are cohabiting with their partners, and though they’re less likely than married couples to pool all their money, many roomies-with-benefits do share major expenses. That’s partly a matter of convenience, says Sonya Britt, Ph.D., an associate professor of personal financial planning at Kansas State University, but there can also be a wishful-thinking element: the idea that merging your finances makes you more of a couple.

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Lesson learned: Money and relationships, from platonic to romantic, can be a volatile combination. The key is communication, says Britt. “Make a clear plan ahead of time about purchases and expenses—who’s going to pay for what, and how would things be divided later? In Shelly’s case, she could have said, ‘If I want something for my house, like a hot tub, I pay for it, and you provide the labor. If you want something for my house, that’s your gift to me.’”

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And if you’re contemplating sharing a big purchase, talk about what would happen if you don’t stay together. It may feel awkward to discuss the potential of splitting up, but—as with a prenup—it means you negotiate when you’re friends, not enemies.

For more relationship advice, check out the April 2017 issue of Women’s Health on newsstands now.