"A ‘spillover’ effect found in consensually nonmonogamous relationships"
First, a short report on the study in PsyPost, a psychology news feed:
A ‘spillover’ effect found in consensually nonmonogamous relationships
By Eric W. Dolan
New research on consensually non-monogamous relationships indicates that having one partner who meets your sexual needs is linked to increased satisfaction not only in that relationship, but also in a concurrent relationship. The study was recently published in the Journal of Social and Personal Relationships.
...The study of 1,054 individuals in consensually non-monogamous relationships found evidence that sexual need fulfillment in one relationship could “spill over” to another relationship. The researchers found that having sexual needs met by one partner was associated with greater satisfaction with another partner.
“I think one takeaway even for people who are not in CNM relationships is that it might be possible for need fulfillment in one relationship to have benefits for other relationships,” [coauthor Amy ]Muise told PsyPost. “Of course, there may also be times when seeking need fulfillment outside of a relationship may not be beneficial.”
“In the future, it would be ideal to look at need fulfillment (beyond sexuality) across relationships. So how does perceiving a partner as motivated to meet your needs influence your relationships with friends and family members?”
The study has some limitations.
“One major caveat is that this sample includes people who are consensually involved in multiple relationships, it does not suggest benefits to non-consensual additional relationships,” Muise noted. “One question that needs to be addressed is why perceiving one partner as responsive is beneficial for (or detracts from) another relationship — Are people having more needs fulfilled, etc?”
The study, “Sexual need fulfillment and satisfaction in consensually nonmonogamous relationships“, was authored by Amy Muise, Andrew K. Laughton, Amy Moors, and Emily A. Impett.
The article (June 16, 2018).
● As reported in more depth on the feminist site Bustle: Non-Monogamous Couples Who Are Satisfied In One Relationship Are More Likely To Be Happier With Another, Study Finds (June 18)
By Lea Rose Emery
If you apply the "grass is always greener" theory to poly and consensually non-monogamous relationships, it might seem like everyone would constantly be unsatisfied. They would be thinking about what they don't have in one relationship and what they do have with another person. But yet, people have very happy poly and non-monogamous relationships. A new study... shows why that might be the case. In what they're dubbing a "spillover" effect, researchers recently found that for consensually non-monogamous couples, being satisfied in one relationship can "spill" over into another.
There were actually two studies that looked at 1,054 individuals in consensual non-monogamous relationships. In the first study, they found that those who were more sexually fulfilled in their primary relationship also experienced greater relationship satisfaction in their secondary relationship. The second study was a little more complicated. Researchers looked at how satisfaction in a secondary relationship affected the primary connection. They found that men who were more sexually fulfilled in a secondary partnership also reported higher satisfaction with a primary partner, but women who were more sexually fulfilled with a secondary partner were less satisfied with their primary partner.
But overall, it seemed like the "spillover" effect was a positive one — satisfaction in one relationship translated into satisfaction in another. The interesting thing was that researchers thought this might extend outside of non-monogamous relationships. ... "In terms of monogamous relationships — I have been thinking about this more broadly, like whether having non-romantic relationships (friends, family) who are communal/ fulfill needs could be associated with more satisfaction in a romantic relationship and vice versa," Muise says. ...
● The paper's abstract:
Consensually nonmonogamous (CNM) relationships allow individuals to fulfill their sexual needs with multiple partners, but research has yet to investigate how having one’s sexual needs met in one relationship is associated with satisfaction in another relationship. We draw on models of need fulfillment in CNM relationships and theories of sexual communal motivation to test how sexual need fulfillment in one relationship is associated with satisfaction in another, concurrent relationship. Across two studies, individuals in CNM relationships (N = 1,054) who were more sexually fulfilled in their primary relationship reported greater relationship satisfaction with their secondary partner. In Study 2, men who were more sexually fulfilled in their secondary relationship reported greater relationship satisfaction with their primary partner, but women who were more sexually fulfilled with their secondary partner reported lower sexual satisfaction in their primary relationship. Implications for communal relationships and need fulfillment are discussed.
The full paper is behind a paywall; get it through an academic library. Reference: http://journals.sagepub.com/doi/abs/10.1177/0265407518774638
So in the poly context, it's not a competition. The authors don't go here, but I will: Compersion in humans is normal and, when societal conditions permit, fairly common.