Researchers examined data on young women and found a troubling pattern: the likelihood of experiencing intimate partner violence rises significantly during periods when the partner has another sexual relationship. This holds both for cases where the couple had no explicit monogamy agreement and for situations where such an agreement was violated. After such events, relationships more often break up.
The work, published in the Journal of Marriage and Family, is based on an analysis of data from the Relationship Dynamics and Social Life (RDSL) study. It involved 1,003 young women aged 18-19 from a county in Michigan (USA). The participants were followed for 2.5 years, until they reached ages 20-22.5. The study focused on early pregnancy but also collected detailed information about romantic relationships.
The scientists distinguished two types of non-monogamy: with uncertain consent (when there is no explicit monogamy agreement) and without consent (infidelity in monogamous relationships). The results showed that 28% of relationships involved partner violence, and 52% of participants experienced it at least once. Partner infidelity was reported in 7% of relationships, and non-monogamy with uncertain consent in 16%.
The analysis showed that in the weeks when the partner had another sexual relationship, the likelihood of violence by him increased. This applied to both types of non-monogamy. In addition, after such events the likelihood of the relationship breaking up increased. The authors interpret the results in terms of expectancy violation theory: infidelity or uncertainty in a relationship is perceived as a serious violation of norms, which leads to a reassessment of the relationship and, possibly, to a breakup.
The researchers note that their work contributes to understanding the dynamics of young relationships, but it has limitations. In particular, it does not report on the link between the participants' own non-monogamous behavior and violence, or on how often the non-monogamous behavior of partners and of the women themselves coincided. In addition, violence perpetrated by the participants was measured differently from violence by their partners.