Here's What Gets Cohabiting Couples to Put a Ring on It

No one factor determines whether a couple that moves in together will ultimately tie the knot. But finances are a big predictor, and for anyone clinging to the breadwinner model of partnership, grab your hats: Couples are most likely to marry when their salaries equalize.

One sociologist at Cornell University has just released research suggesting that couples tend to get married when their combined income matches that of their peers, and they're able to achieve milestone investments like homeownership. They're even more likely to stick together if they each earn about the same amount. Unfortunately, that does have a flip side — economically disadvantaged couples tend to separate more often.

"Equality appears to promote stability," said study author Patrick Ishizuka in a press release. "Equality might increase commitment or cooperation between partners since they're bringing similar economic resources to the relationship."

This isn't the only side to this story, however. This week, Georgia State University researchers also released a study suggesting that for some, marriage may actually have health benefits. Their data found that married couples with a combined household income of less than $60,000 show fewer symptoms of depression than unmarried people earning a comparable amount.

"For people who are earning above $60,000, they don't get this bump because they already have enough resources," said co-author Ben Lennox Kail in a press release. "About 50 percent of the benefit these households earning less than $60,000 per year get from marriage is an increased sense of financial security and self-efficacy, which is probably from the pooling of resources."

Marriage is a huge decision no matter what, and while this data shouldn't sway anyone way or another, it does offer a window on the invisible hand and the ring that goes with it.