Younger generations aren’t the only ones cohabiting these days. Research by sociologist Susan Brown and her colleagues at Bowling Green State University find that the number of Americans over age 50 who are living with their romantic partners – but are not married – has increased from 1.2 million in 2000 to 2.75 million in 2010.

As MSN reports, this arrangement provides older cohabitators many of the benefits of marriage without the potential economic risk.

Older couples may want to protect their individual nest eggs so they can pass the inheritance down to their kids. They also may not want to jeopardize a pension, Social Security payment or other benefit they are receiving because they are divorced or widowed. And they may not want to be financially responsible for the other person’s health care bills.

A “been there, done that” attitude is also contributing to the trend, Brown says. According to the team’s research, “71 percent of older couples living together were divorced, and another 18 percent were widowed.” The prospect of re-entering a union may be particularly unappealing for women who feel an “underlying expectation” to take care of their husbands.

Alternative relationships other than cohabitation also appear to be on the rise. Although the numbers aren’t as clear, Brown notes a group engaged in “living apart together.” “They’re very committed to each other ,” she explains, “(but they) don’t want to give up the autonomy that they have.”