Gone on a double date recently? If you haven’t, it might be time to call up some friends to make plans:  according to new research out of the University of Maryland, married couples that hang out with other couples have stronger relationships — and are more attracted to their partners.

“We found that there was a number of benefits to having couple friends,” said Kathleen Holtz Deal, UMD associate professor. “One of them is people actually use their couple friends as a model to emulate and a model to say, ‘Let’s never do that.’ ”

Deal and her co-researcher, Geoffrey Greif, found that couple friendships can be divided into three broad categories:  Seekers, Keepers, and Nesters. Broadly speaking, Seekers are extroverted types. They enjoy mixing socially and meeting new people. Keepers are more interested in maintaining current friendships than in forging new bonds, while Nesters prefer to stay at home and hang out with one or two other couples.

How do you find these people? Deal notes that the couples they spoke with”really liked sharing values and interests with the couples that they were friends with. So if you have opportunities to meet people in some type of situation or environment in which you could be sharing similar values or something, that might be good. For some people, it might be a cause or a religious organization of some kind. Meeting people under those circumstances at least indicates that you have something in common, and something that you might be able to build on.” The book that Deal and Greif wrote based on their research, Two Plus Two:  Couples and Their Couple Friendships, is available here.