Money and relationships can produce strange results. A University of Pennsylvania study Fatal (Fiscal) Attraction: Spendthrifts and Tightwads in Marriage has found that big spenders tend to marry tightwads. Opposite attract. Which might be a worry.

"We found that the more people were dissatisfied with their own emotional reactions toward spending, the more likely they were to be attracted to a mate with opposing emotional reactions toward spending,'' the researchers say."This complementary attraction pattern held not only when one spouse assessed both their own and their partner's emotional reactions toward spending, but also when each spouse in a marriage
assessed only their own emotional reactions toward spending."

Despite this, the research found that people didn't necessarily go out seeking their opposite. It just happened.

The alarming part about the study is that the different approaches to money resulted in more conflict, and unhappier marriages. And that's the real concern, particular if, as the evidence suggests, people don't know what they're getting.