By Emma Young

As everyone knows, the nature of romantic relationships usually changes over time. An early period of intense attraction tends to develop into a less fiery, deeper attachment bond. According to evolutionary arguments, the early stage, which typically lasts a few years, gives the pair the time and proximity that’s required for developing a deeper nurturing, supportive – and predictable – relationship. While this type of attachment is important for rearing children, and for ongoing wellbeing, it’s not necessarily great news for passion.

“Though passion can still be experienced in the later stages, it tends to decline, on average,” note the authors of a new study, published in Social Psychology. They go on, however, to report that there is a group of people who experience higher sustained levels of both supportive warmth and nurturance and eroticism than is typical in relationships – only, they don’t get both from the same partner.

Rhonda Balzarini at York University, Canada and colleagues conducted the first empirical test of differences between eroticism and nurturance among participants who were in either a monogamous or a polyamorous relationship. Someone in a polyamorous relationship typically has a primary partner (they usually live with this person who is often their spouse and the co-parent of their children if they have any) and also, with the consent of that person, a secondary romantic partner. Relationships with secondary partners tend to last for at least a few years, allowing for some nurturance, as well as sex.

The researchers recruited their polyamorous participants – more than one thousand of them – from Facebook and Reddit groups dedicated to polyamory discussions. These individuals had been with their primary partner for an average of seven years, and with their secondary partner for two. They completed questionnaires that asked about levels of nurturance (to what extent they felt a strong sense of security, love, warmth, etc) and eroticism (including their felt levels of desire and lust, and sexual excitement) in each relationship, how close they felt to each partner, and also their levels of sexual satisfaction. The team also collected similar data on over two thousand monogamous people, who had been in an exclusive relationship for an average of 17 years.

As the researchers had predicted, the polyamorists enjoyed more nurturance from their primary than from their secondary, partners, on average, and gave higher eroticism ratings to their secondary relationships. Overall, their eroticism ratings were higher than for the monogamists. More surprisingly, their nurturance ratings for their primary relationship were higher than those reported by the monogamists. These differences held even when the researchers controlled for the differences in relationship length between the two groups.

There were also some differences in sexual satisfaction and closeness. Among the monogamous participants, eroticism and nurturance were both positively associated with sexual satisfaction and closeness. For the polyamorists, nurturance was similarly linked to feelings of closeness in both their relationships, but eroticism was only associated with sexual satisfaction and closeness in their secondary relationships,

“These findings have broad research implications for the study of romantic relationships,” the researchers write. “The belief that monogamy is superior to other relationship orientations is a fundamental and often unquestioned assumption underlying contemporary theories of the development of romantic relationships and intimacy.” And yet, they go on: “The findings suggest that polyamory may provide a unique opportunity for individuals to experience both eroticism and nurturance simultaneously.”

There are various caveats, however. An important one is that, when it comes to the nurturance data, someone who tolerates their partner having an ongoing relationship with somebody else is arguably likely to be a more supportive individual in the first place – and/or it’s likely that a deeper attachment is required for a primary partnership to be sustained during polyamory. The results can’t be seen to imply than any couple could decide to take on secondary partners and expect to enjoy the benefits reported by the polyamorists in this study.

Still, the research does highlight some possible benefits of being polyamorous, at least for some people. The researchers would now like to see work exploring whether relying on different partners to meet nurturance and erotic needs, rather than just one, could enhance life satisfaction and personal wellbeing.

—Eroticism versus nurturance: How eroticism and nurturance differs in polyamorous and monogamous relationships

Emma Young (@EmmaELYoung) is Staff Writer at BPS Research Digest