You may be familiar with the film Bob & Carol & Ted & Alice and its characters’ anxious explorations of sexual liberation—about 50 years ago. The movie, released in 1969, captured a moment in America’s 20th century sexual revolution as two couples, who are close friends, experiment with having sex outside their marriages. Their attempts at negotiating sexual encounters and their spouses’ reactions are met with varying degrees of success—and embarrassing failure. But that was half a century ago. What does the landscape look like now, in the 21st century?

And how are you feeling about your monogamous relationship?

The question seems pertinent not out of nostalgia for an old movie or an old sexual movement, but because there’s something happening today: According to recent surveys, 3% to 7% of adults in the US and Canada are in “open” relationships, meaning that both partners agree that’s it’s ok for either of them to have multiple sexual and/or romantic relationships. That’s a lot of people (about eight million to 18 million in the US alone) doing something that barely registers as a blip in regular conversation or in the media. The academic term for these relationships is “consensually nonmonogamous,” or what sociologists refer to as “CNM.”

Are these people happy? That’s what researchers at the University of Guelph in Canada and New York University’s Institute for the Study of Decision Making recently set out to discover. The researchers note that there’s still a lot of stigma surrounding this lifestyle choice. Many people believe that people who are in CNM relationships are immoral bed-hoppers and that their relationships are less stable, loving and satisfying than monogamous ones.

But that’s not what’s really happening.

THE TRUTH ABOUT NONMONOGAMOUS RELATIONSHIPS

To examine the quality of these relationships, the researchers compared the experiences of 142 men and women between the ages of 20 and 70 who were in CNM relationships with those of 206 men and women who were in monogamous relationships. Most monogamous respondents were married, living with or seriously dating one person. Each CNM adult surveyed had, on average, two partners—a primary one and one other.

All participants were asked, via an Internet questionnaire, about their satisfaction with their current relationships (i.e., their primary partners for those who were nonmonogamous), including how committed they were to their partners, the quality of their communication (such as whether they confided in their partners) and how happy they felt.

The study’s stereotype-busting conclusion: People in consensually nonmonogamous arrangements were, on average, just as content with their primary relationships—including the sexual aspects of these relationships—as those in monogamous relationships.

You might speculate that people who seek sex outside of their primary relationships do so because they are sexually dissatisfied with them, but that’s doesn’t appear to be the case. It is, of course, possible that the ability to openly have sex outside the primary relationship takes pressure off of the sexual aspect of that relationship, making it easier to feel satisfied with it. As the researchers point out, people today expect an awful lot from their spouses or live-in romantic partners—not only love and sexual fulfillment, but also social and financial support. High expectations can put stress on a marriage or relationship, making it harder, by definition, for each person to have his or her needs fulfilled. Nonmonogamous partners may be reducing the pressures of monogamy in a wide variety of ways…not only sexual.

Unfortunately, this study can’t answer such questions about motivation. But it did find one aspect to a couple’s sex life that made a difference in terms of satisfaction—and has nothing to do with whether those relationships were monogamous or non-monogamous.

THE KEY TO RELATIONSHIP HAPPINESS

In the end, the researchers found, whether a couple was monogamous or not was not a determinant of overall contentment in the relationship. In terms of sexual satisfaction in particular, something else was much more important: motivation. Study participants who were having sex for so-called “intrinsic” reasons—to be close to their partners or to fulfill their own sexual needs—had more satisfying relationships than those who were driven by less intrinsic motives, such as a desire to avoid conflict or a fear of losing the relationship. Every relationship is unique, but the agreement that couples have for monogamy appears to be less important for happiness than authenticity. As Bob or Carol might say, “Insight!”