A few months ago, my friends — a colleague and her partner, who share my boyfriend’s affinity for cute-goth Instagram illustrators and metal — moved to New York. We had planned to move there, too, but life has kept us in Boston for at least another year. Their move has left a void in our social lives.

We have other friends, couples and singles alike, and we love them. However, the loss of our ride-or-die couple friends has been a hit we were not prepared for.

Forging friendships as adults is challenging. It’s even tougher to find two couples where everyone likes one another. Why do couple friends seem so imperative to our romantic lives? Why are some better than others? And how do we make new ones? 

“Getting together with another couple can make your partnership seem stronger,” Geoffrey L. Greif, a professor at the University of Maryland School of Social Work and the co-author of Two Plus Two: Couples and Their Couple Friendships,” told me. “You get to see your partner in a great light — they’re interacting, having fun, happy, that makes them more attractive. That’s the upside.”

Greif and his writing partner Kathleen Holtz Deal explored the dynamics of couples and their couple friends, and found that heterosexual relationships benefited best when they were able to connect on a deep emotional level with another couple. 

They found gender roles within romantic relationships are more fluid when intimately interacting with a fellow couple. “Research tends to say men get drawn into conversations and face-to-face interactions he might not feel comfortable doing on their own,” he said. “Women could then use that time with another couple to get her husband or partner to talk about things he wouldn’t otherwise.”

Greif and Holtz Deal placed couples in three categories: seekers, extroverts actively searching for new social relationships; keepers, those who feel fulfilled within the confines of their relationship and are happy with an intimate group of confidants; and nesters, introverts who prefer to stick to a party of two. Greif, who identifies as a seeker, and his nester wife often find themselves negotiating to form meaningful friendships with other couples.

“She pulls me in a bit, and I pull her out a bit, and we meet in the middle,” he explained. “Knowing those roles and having that discussion should give couples a language.” And in developing that social contract, the relationship deepens its bonds.

The number one reason for couple friends: having someone else to talk to.

“The biggest issue for every couple, across all the books, is what to do with all the time,” Greif said.

Number two? Having something to talk about.

“Take people like my parents — they’re interesting people, but their conversations are very limited to their own perspectives, in that, they’re not expansive,” says Laurel House, celebrity relationship coach. “If you have interesting couples in your life, you have different perspectives, and conversation can expand, and you feel more interesting, and more confident.”

Improving conversation between couples was a main goal for Cory Nitschelm, founder of Coupler, a soon-to-be-released swipe-based social app for double dates.

“We believe making couple friends strengthens a relationship from an external and an internal perspective,” he said. “That way, it’s not just the two of you doing the same things, stagnating.”

Nitschelm saw a market need for recent city transplants to find fellow couples and thus build a friendship network that suits them both. Coupler, which is now available on Google Play, syncs both partners’ accounts so they can browse other couples’ profiles together and find matches based on common interests and location.

“Sometimes when you’re in a couple and have individual friend groups and you try to just add your significant other into that world, it can be awkward,” Nitschelm explained. “This way, it helps you start on the same footing with new friends together.”

Couple friendships aren’t always a positive. Like all friendships, couple friendships can be toxic. House explained that if the connection with another couple is only surface level and not deep, such a friendship “can actually hurt the [romantic] relationship because you might get bored and have a bad time.”

Some couples use their friendships as an audience to overcompensate — “our relationship is so great, let us tell you about it!” — or the reverse: Couples can spar, nitpick and compare.

“If you’re bringing out the negativity in your relationships, you might be bringing out the negativity in that other couple’s relationship, too,” House said.And they’ll start to realize, ‘Every time we hang out with that couple, we get in a fight, too. Why is that?’ No one wants to be around negative people. It’s entertaining at first, but we don’t want to actually live it. The reason you have couple friends is to feel better, not worse.”

Also risky, House noted, are couples who aren’t equally enthusiastic about pursuing the friendship. “You have to both like the other couple or one person is always going to feel like they have to go,” she said. “You have to be all in.”

Adult friendships are ridiculously hard to come by — couple friends even more so. There was something so satisfying about seeing my boyfriend find a friendship that made him as happy as one of my own. And it was gratifying to get to know the man who made another person I love, my friend, so happy. 

Our adventure-driven, politically like-minded, fellow brown-liquor-drinking, childless friends are even more rare and valuable than I already thought. And a four-hour bus ride isn’t that bad anyway.

Read more:

How to make and keep friends as an adult

How do couples live in tiny homes without killing each other?

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