Although plural marriages are illegal in the U.S. and many westernized countries, they are legal in over 850 different societies,1 and consensual non-monogamy (e.g., open marriage à la Newt Gingrich, polyamory, swinging, and other sorts of arrangements) are becoming increasingly popular.2 TV networks have tapped into this interest: Big Love and Sister Wives, fictional and reality TV series on HBO and TLC, respectively, show the challenges of living in a plural marriage in the United States. The characters and individuals on the shows struggle with problems many monogamous couples face, like getting the bills paid on time and being able to communicate with each other when the kids are screaming. These shows also highlight a number of other problems that are somewhat unique to, or at least exacerbated in, non-monogamous couples, such as jealousy and favoritism.
So what might be some benefits of being in love with, and even committed to, multiple partners? This is an interesting question, because in many parts of the world being non-monogamous is often labeled as deviant, immoral or unnatural.2 Is the stigma justified? It may be surprising that there are a number of benefits to plural relationships. As a cultural tradition, plural marriage has been viewed as an adaptive practice in parts of the world where infant mortality is high; having more wives ensures that men have more children survive to adulthood. In agricultural societies, families often work their own land, and more children means more free labor. Additionally, when there is a shortage of available mates, such as after times of war, men or women may also be more open to “sharing” a partner.3 For a number of religious and economic reasons, polygamy as a practice in some societies such as Tanzania has been declining,4 but this does not mean that men in such societies remain faithful to one wife-- many still have “outside” wives that their legal wife does not know anything about.5 Men and women in such societies often have several (usually 2-3) intimate partners to fulfill sexual, economic, and intimacy needs.6 Rather than expecting these traits to reside in one partner, they find them in multiple relationships.
Is it really so different in societies like the U.S., where plural marriage is illegal? Many individuals do not practice monogamy, even when they claim to be exclusively monogamous! Rates of hidden infidelity are quite high (60-70% in some samples),7 so clearly many individuals have multiple partnerships. Rather than hiding such relationships, some couples create clear expectations and agreements on what sexual behaviors and commitments both partners are okay with outside of their primary relationship, and research shows that there are not significant differences in relationship satisfaction between these types of couples and monogamous ones.8 So while there may be a lot of cultural, religious, and personal resistance to the idea of having multiple partners to love, there are also a number of benefits to consider (for a counter-argument, see here).
1 Westoff, C. F. (2003) Trends in marriage and early childbearing in developing countries. (DHS Comparative Reports No. 5). Calverton, NY: ORC Macro.
2Barker, M. & Landridge, D. (2010). Whatever happened to non-monogamies? Critical reflections on recent research and theory. Sexualities, 13, 748-772
3Cook, C. T. (2007). Polygyny: Did the Africans get it right? Journal of Black Studies, 38¸232-250.
4Meekers, D., & Franklin, N. (1995). Women’s perceptions of polygyny among the Kaguru of Tanzania. Ethnography, 34, 315-329.
5 Ezeh, A. C. (1997). Polygyny and reproductive behavior in sub-Saharan Africa: a contextual analysis. Demography, 34, 355–368.
6Yahya-Malima, K. I., Matee, M. I., Evjen-Olsen, B., & Fylkesnes, K. (2007). High potential of escalating HIV transmission in a low prevalence setting in rural Tanzania. BMC Public Health, 7(103), 75-82.
7Vangelisti, A. L., & Gerstenberger, M. (2004). Communication and marital infidelity. In J. Duncombe, K. Harrison, G. Allan, & D. Marsden (eds.), The state of affairs: Explorations in infidelity and commitment, pp. 59-78. Mahwah, NJ: Lawrence Erlbaum Associates.
8Blasband, D., & Peplau, L. A. (1985). Sexual exclusivity versus openness in gay male couples. Archives of Sexual Behavior, 14, 395-412.
Dr. Jennifer Harman - Adventures in Dating... | Science of Relationships articles | Website/CV
Dr. Harman's research examines relationship behaviors that put people at-risk for physical and psychological health problems, such as how feelings and beliefs about risk (e.g., sexual risk taking) can be biased when in a relationship. She also studies the role of power on relationship commitment.