When Jody MacMillan and his part­ner Amanda first dated seven years ago, he quickly noticed a big difference in the way they handled money. “When we went out to dinner, Amanda would always ask for a glass of water instead of pop,” says MacMillan, 32, a customer service representative with Primerica in Barrie, Ont. “Me, I’m the exact opposite. I look for the most expensive drink or meal on the menu and order it. It frustrates her.”

It turns out, though, that Jody’s high-flying spending habits may be one of the reasons his wife was attracted to him in the first place. A new study called Fatal (Fiscal) Attraction: Spendthrifts and Tightwads in Marriages, from the Wharton School of the University of Pennsylvania, found that people who spend less than they’d would like to tend to marry big spenders, while those who spend more than they would like to are drawn to penny-pinchers.

These unexpected partner choices seem to be made unconsciously. If you ask people outright, the study found, spenders say they’d like another spender as a mate, while savers report they deserve a saver. But that’s not the way things turn out in practice. Research by psychologists at the University of California at Berkeley may hold a clue as to why. The psychologists found that while people generally look for partners with similar values, there’s one interesting exception: When it comes to a characteristic that people dislike in themselves, they’ll look for the opposite in a mate. People who don’t like their own spending habits will be attracted to those who spend in the opposite way.

Such pairings make sense, in that tightwads who want to loosen their purse-strings may indeed learn new habits from a free-spending spouse. The only problem is that a lot of arguing seems to take place on the road to redemption. “It might be fun at first to have a partner with an opposite approach to money, but over the course of the marriage, it causes problems,” says Scott Rick, a Wharton lecturer who developed the survey.

If you’re a spender or a saver who is in a relationship with someone who has the opposite approach to money, here are some tips to help make your marriage work:

Compromise
“Give up the dream that your partner will wake up one day and say ‘You’ve been right all along, dear,’” says Ruth Hayden, a financial author and educator based in Minnesota. “It’s not about fault. It’s about compromise.”

Don’t be judgmental
Instead, make a list. “Write down what the person who likes to spend is contributing to the marriage and what the saver is contributing,” says Amanda Mills, founder of Loose Change Financial Therapy.

Have a weekly meeting about money
The meeting should take place in the same place every week and the main rule is that you are not allowed to fight. “It’s a no-conflict zone,” says Mills. “No blaming, no shaming.”

Agree to long-term goals
 Find a long-term goal that you and your partner can agree on. “Both Amanda and I wanted a house and we wanted to be debt-free,” says Jody MacMillan. “By focusing on those goals, I adjusted my spending behavior. We’re free of personal debt now and we own our own home.”