Not all romantic relationships between consenting adults involve only two people. For nearly one-fifth of U.S. adults at some point in their life, those relationships have included three or more.
Having more than one romantic partner at time, with the consent of all involved, is called “consensual non-monogamy.” While it’s much more common than most people realize, people who practice it face stigma and prejudice.
A recent study at UC Davis tested whether a classroom curriculum could reduce that stigma. Not only did the class reduce prejudice against consensual non-monogamy, but it also increased all students’ relationship skills and sense of belonging. The study was published in the American Psychological Association journal .
“This is a very exciting study because it replicates and extends this very robust body of evidence that inclusive pedagogy and curriculum practices benefit all students,” said Rose Bern, a Ph.D. candidate in psychology at UC Davis and the study’s lead author. “That can have a pretty profound effect on overall well-being and acceptance in society on a larger scale.”
What is ethical non-monogamy?
Ethical non-monogamy is another term for consensual non-monogamy, which the as, “relationships in which all partners give explicit consent to engage in romantic, intimate, and/or sexual relationships with multiple people.” Consensual non-monogamy is not the same as cheating, which a found has a high level of stigma in the U.S.
“Consensual non-monogamy is heavily stigmatized,” said Bern. “It's often misperceived as a form of cheating when in fact all parties are agreeing to this. All parties are consenting. It's mutual. It’s also really common.”
A found that roughly 20% of Americans reported practicing consensual nonmonogamy at some point in their lives. A found that while at least 5% of people in North America are in a consensually non-monogamous relationship, many still experience stigma.
In practice, relationships that consensually involve multiple partners can take many different forms. They are also particularly common among people who identify as LGBTQ+.
Reducing prejudice with a classroom curriculum
A large body of research has found that classroom curriculum can effectively reduce prejudice against people who identify as LGBTQ+. Bern and her co-authors designed their study to produce similar results for consensual non-monogamy. The study took place in 2025, and the analysis included 297 undergraduate UC Davis students who enrolled in a psychology elective course titled, “Relationship Science.”
At the start of the study, participants held more negative views of consensual non-monogamy. By the end of the study, those attitudes changed significantly. Participants were much less likely to consider consensual non-monogamy as either “dysfunctional” or “unhealthy.”
However, at both the start and end of the study, participants were roughly equally likely to consider this type of relationship “immoral.”
The curriculum did not shift attitudes toward LGBT+ people, but this may be because participants already held positive views.
“Each module was presented in a non-critical manner that allowed me to educate myself on topics, without the influence of possible pre-conceived notions,” said Claire Mitchell, a who took part in the study before graduating from UC Davis. “I believe this ‘matter of fact’ way of teaching is beneficial to all students as it prevents us from feeling alienated and opens us to learning with minimal bias.”
LGBTQ+ identity, neurodiversity and romantic preferences
Prior research has found that people who are neurodivergent, which could include having autism or other differences in the way their brain processes information, overwhelmingly identify as LGBTQ+. In the study at UC Davis, about 70% of participants who identified as neurodivergent reported a higher increase in belonging than their neurotypical peers.
Bern said that this finding may result from how the class included discussions of neurodiversity that didn’t treat it like a deficit or a form of mental illness. The class also included a guest lecture dedicated to neurodiversity and relationships.
“There's clearly understudied interplay between neurodiversity and relationship diversity,” said Bern. “That neurodivergent students reported higher acceptance and lower prejudice towards non-monogamous relationships could be a function that the vast majority of them identified as queer.”
Bern, who recently accepted a post-doctoral researcher position at the , also created a novel measure of how people feel about their own relationship skills, and participants reported increases in this measure. This increase came regardless of how participants identified by gender or sexual identity.
“I'm hopeful that future work can develop targeted prejudice-reduction interventions that help reduce stigma toward not just broad LGBTQ+ communities but relationship diversity that is commonplace in LGBTQ+ spaces,” said Bern.
Co-author contributions come from LeMoyne College, the Illinois Institute of Technology, Chapman University and Indiana University.