A new study tracked people who planned to open up their romantic relationship to include other partners for two months. The findings, published in Social Psychological and Personality Science, indicate that engaging in consensual non-monogamy is associated with some increases in sexual satisfaction — but does not have much of an impact on other aspects of one’s relationship.

The idea for the study primarily came from Annelise Murphy, an undergraduate psychology student at Western University. “She wanted to gain some research experience by conducting her own independent project. She was particularly interested in consensual non-monogamy (CNM), and whether the experience of practicing CNM might be better or worse for certain individuals,” explained Samantha Joel, an assistant professor at the University of Western Ontario and co-author of the research.

“My own research interests are on relationship decisions, so this project was the natural merger between her interests and mine,” explained Joel, who is also the head of the Relationships Decision Lab.

“How do people choose to open their relationships up to other partners, and what happens afterward? How do their relationship change? Do the consequences of opening up a relationship depend on a person’s reasons for wanting to do so? We decided to conduct this exploratory study to learn as much as we could about that relationship transition.”

For their study, the researchers recruited 233 individuals currently in a monogamous relationship who had expressed a desire to try swinging, an open relationship or polyamory (but had not done so yet.) The participants completed assessments of relationship quality, life satisfaction, sexual satisfaction, and motives for engaging in consensual non-monogamy. Two months later, the participants completed a follow-up survey.

The relationship quality assessment asked the participants to indicate how well their partner met their needs, how much they loved their partner, and how many relationship problems they were experiencing, among other things.

More than half of the participants, 155 individuals, reported that they had in fact opened their relationship over the two month span. The researchers found that participants who opened their relationships tended to experience positive changes in sexual satisfaction, while those who did not tended to experience negative changes in sexual satisfaction over the course of the study.

When it came to relationship quality and life satisfaction, on the other hand, there was no meaningful difference between those who opened their relationships and those who did not.

“On the one hand, there’s an idea out there that turning your monogamous relationship into a non-monogamous one is an effective way to ruin that relationship. On the other hand, consensual non-monogamy is sometimes talked about as though it’s an elixir for relationship problems. The biggest takeaway from the current data is that we found no support for either of these ideas. People who opened up their relationships to other partners were no more or less happy with their relationships after they opened up than they had been at the beginning of the study,” Joel told PsyPost.

“We did find that people who opened up their relationships were subsequently more sexually satisfied, both compared to before they had opened up, and compared to the portion of our sample who thought about opening up but didn’t. This was particularly true for people who had the goal of addressing sexual incompatibilities within their primary relationship. So, although engaging in CNM may not improve people’s relationships per se, our results tentatively suggest that it could help people’s sex lives.”

The findings point to overall trends, but the results may vary for individual couples — especially when one partner wants to open the relationship while the other does not.

“We specifically recruited people who were thinking about opening up their relationships, and so our participants were all at least somewhat enthusiastic about CNM by definition. The current results probably wouldn’t generalize to people who hold negative attitudes about CNM. Another major caveat is that we did not collect partner reports, and so we cannot say how our participants’ partners felt about the experience of opening up their relationships,” Joel explained.

“People self-selected into the ‘open’ group by choosing to engage in CNM. That self-selection limits our causal conclusions: we don’t know why some people in our sample chose to open up while others didn’t, and what other third variables (e.g., other things happening in their lives) might explain the differences between the groups or between the time points.”

In addition to recruiting both couple members, future research should also include more partner-related assessments and examine the long-term impact, the authors of the study advised. “We only followed our participants over a couple of months, and so these data cannot speak to the long-term effects of opening up a relationship to other partners,” Joel noted.

The study, “A Prospective Investigation of the Decision to Open Up a Romantic Relationship“, was authored by Annelise Parkes Murphy, Samantha Joel, and Amy Muise.