The majority of prior theoretical and empirical work on polyamory has focused on polyamory as part of a general category of CNM, and has compared CNM relationships to monogamous relationships. The present research, using a large community sample, is one of the first to empirically investigate differences specifically in polyamorous individuals’ perceptions of their primary and secondary relationships, the most commonly practiced configuration among polyamorists. We first provide an overall summary of our findings and then discuss the implications of specific findings. We conclude by offering directions for future research.

Summary of results

Our analyses tested 11 pre-registered hypotheses that can be conceptually grouped into four categories: (1) acceptance and secrecy, (2) investment and commitment processes, (3) relationship communication, and (4) percentage of time spent on sexual activity. Based on our main and exploratory analyses, there is evidence that primary relationships are associated with certain rewards, namely, greater acceptance, less secrecy, higher investment, and commitment levels. There is also a greater amount of communication in primary compared to secondary relationships. However, secondary relationships may offer at least one reward of a newer relationship; percentage of time spent on sexual activity was higher among secondary relationships than primary relationships.

Relationship acceptance and secrecy. We conceptualized expressions of acceptance from important others to be one potential reward for primary relationships and the perception of a lack of acceptance to be one cost for secondary relationships. This was suspected, in part, because polyamory is not widely accepted and is a socially stigmatized relationship configuration [22]. Thus, while acceptance from friends and family serves as an important relationship reward, it is unlikely that such acceptance will be afforded to secondary relationships to the same degree as primary relationships given that primary relationships could more easily pass for monogamous relationships. Indeed, some of the strongest and most robust effect sizes in our series of analyses arose from differences in perceived relationship acceptance. Overall, though, levels of acceptance were high for participants in this study and well above the midpoint of the scale, with the exception of family acceptance of secondary partners. Consistent with differences in acceptance, our results suggest that romantic secrecy is greater with secondary relationships. Although we did not test reasons for relationship secrecy in this study, it is possible they could be reflective of internalized beliefs about how people ought to think or behave. Within a polyamorous relationship, additional relationships beyond the initial dyad may be kept secret to comply with socially accepted norms, which may remain influential even when stigma or lack of acceptance are not actually observed or reinforced. Thus, individuals within polyamorous relationships could choose to maintain their secondary relationships in secrecy, either due to a lack of acceptance from friends and family, or alternatively, secrecy could be a preventative measure to protect against the potential lack of acceptance. Future research is clearly needed to address reasons for romantic secrecy. Future research should also explore the potential costs associated with “coming out” as poly (e.g., problems with one’s family, friends, and career), as well as the potential benefits (e.g., by relieving the stress and burden of concealing a major secret) [37].

Relationship investment and commitment processes. Our results suggest that individuals invest more into primary compared to secondary relationships. With regard to investments in romantic relationships, allocation of certain resources (particularly those of a tangible variety, such as money and possessions) is limited in the sense that allocating such resources to one relationship leaves less to be allocated to additional relationships. One implication of this is that investments in a primary relationship may limit the resources available to invest in secondary relationships. Additionally, because secondary relationships are more likely to be socially devalued than primary relationships—as indicated by lower acceptance from friends and family—people in such relationships may invest significantly less in their secondary relationships due to their marginalized nature [34]. Further, or alternatively, because investments usually take time to accrue in a relationship, participants may invest less in secondary relationships simply because those relationships have not existed as long as primary relationships. We tested this possibility in our exploratory analyses, and although difference in relationship length had a significant association with difference in investment, this association did not wholly account for the difference between investment in primary and secondary relationships. Thus, it seems likely that a combination of factors could help account for our finding that investments were lower in secondary compared to primary relationships. In future research, it would be worth distinguishing among different types of investments (i.e., tangible vs. intangible) in primary and secondary relationships. Tangible investments (e.g., possessions, children) are not easy to distribute equally across relationships, and government-sanctioned marriage typically requires that these investments be tied to a single partner. In light of this, one might predict that primary and secondary relationships would differ when it comes to tangible investments, but not with respect to intangible investments (e.g., time, effort, shared memories), given that the latter are equally available in all relationships [46]. With respect to quality of alternatives in polyamorous relationships and consistent with our prediction, poorer quality of alternatives were reported for primary relationships. However, this was the smallest difference across our series of analyses to emerge. Our exploratory analyses suggest that quality of alternatives is significantly associated with commitment, such that individuals are less committed to partners when they feel they have more alternatives; however, if they feel they have more alternatives to one partner, they feel more committed to the other partner. One caveat to our finding is that it is unclear who our participants were considering as alternatives (e.g., did secondary and other partners “count” as alternatives to the primary relationship? The fact that alternatives for one partner were positively associated with commitment to the other suggests that at least some participants counted their other partners among their alternatives). While we believe that even if participants were considering their other relationships as alternatives, these results are still meaningful and suggestive of the effects quality of alternatives have on consequential relationship phenomena. In future studies that assess quality of alternatives in polyamorous and other CNM relationships, it would be worth using language that more clearly defines what alternatives mean (e.g., including/excluding other partners that one currently has). Regarding commitment, greater commitment was reported for primary compared to secondary relationships. This result is consistent with previous research findings that marginalization is a significant negative predictor of commitment [34]. Additionally, our exploratory analyses suggest that the individual facets of the Investment model may have some unique associations with commitment. For example, when individuals reported being more satisfied with their secondary relationship they were more committed to their secondary, and also somewhat more committed to their primary. Additionally, as mentioned above, quality of alternatives was associated with commitment processes in that individuals were more committed to their secondary relationship when they felt they had better alternatives to their primary. It is important to note that our results are specific to the measure of investments, quality of alternatives, and commitment used in this study, which was created and validated on individuals in monogamous relationships. Work is needed to create and validate measures of commitment on CNM samples–specifically, in terms of the problems with tangible vs. intangible investments and their meaning in polyamorous relationships (discussed earlier), problems with measurement of quality of alternatives (who counts as an alternative?), and about what commitment really means in a polyamorous context. Again, commitment may mean something different in polyamorous relationships and, as such, we may not fully understand the implications. In other words, this finding does not necessarily mean that secondary partnerships are “lesser” or inherently less functional and, due to the issues noted, results should be interpreted with caution. Taken together, the current results imply that primary relationships are more interdependent than secondary relationships; however, the cross-sectional nature of our data does not allow us to determine whether this equates to greater stability over time with primary compared to secondary relationships. Based upon the existing interdependence literature, one might predict that due to differences in relationship commitment, primary relationships would remain relatively stable, whereas secondary relationships would dissolve more often. Additionally, commitment might mean different things for different relationships. But is this actually the case? This and a number of other interdependence-related questions remain unclear. For instance, when secondary break-ups occur, do new secondary relationships just replace them, leading the same pattern to repeat itself (i.e., primary stability vs. secondary instability)? If so, what is driving this effect—lack of investments, lower satisfaction, greater quality of alternatives, or something else? What are the implications of turnover in secondary relationships for the primary relationship? Does interdependence ebb and flow depending upon the other relationships that one has? Lastly, when a primary relationship does end, do secondary relationships elevate to primary status, or do people seek new primary relationships? How does the secondary partner’s relationship configuration factor into all of this? The current analysis cannot address these questions, but such ideas would be interesting to explore in future studies.

Relationship communication. Another reward primary relationships afford is greater communication about the relationship. Not only did survey respondents report greater communication for primary relationships, but when asked to compare the quality of their communication to most people they know, the quality of communication with primary relationship partners exceeded the quality of communication for secondary relationships. This is understandable for several reasons. First, greater communication may be necessary for primary relationships to endure while other relationships are pursued. For example, the decision to communicate about needs and expectations, to negotiate agreements, schedules, and boundaries, and to work through the kinds of problems that emerge when negotiating polyamory, amongst the typical relational problems that can emerge in any relationship, may simply reflect the high level of interdependence that occurs within primary relationships. We would suspect that greater communication is required within primary relationships to successfully navigate not only those relationships, but also relationships amongst other partners. Additionally, one may argue that because participants report a greater relationship duration with primary partners and are more likely to live with primary partners, the greater time communicating—and even better quality of communication—could be an artifact of simply having greater face-to-face access to the primary partners for such communication to occur more easily. However, our exploratory analyses do not support this reasoning. Specifically, the claim that our results speak more to differences between those who are in longer or shorter relationships or those who live together is not supported by the data. Given different relationship realities of primary-secondary relationships, one question that could better assess the relative importance and role relationship communication has on primary-secondary relationships would be to assess the specific negotiations between these relationships. Future research should explore whether individuals develop different ways of negotiating relationships with primary and secondary partners. While we know primaries experience greater communication, is this because they are better or more practiced at negotiating, or because they are more motivated to negotiate? Furthermore, do more relationships increase the amount of negotiation and communication required or are some people simply better equipped to manage more relationships?