Read the full article at New York Magazine.

In the prologue to her new book, What Love Is and What It Could Be, philosopher Carrie Jenkins is walking through Vancouver, from her boyfriend’s apartment to the home she has with her husband. She wonders at how the romantic love she experiences firsthand is so different than the model presented by popular culture and academic theory alike. “If indeed romantic love must be monogamous, then I am making some kind of mistake when I say, ‘I’m in love with you’ — meaning romantically — to both my partners,” she writes. “I am not lying, because I am genuinely trying to be as honest as I can. But if romantic love requires monogamy, then despite my best intentions, what I’m saying at those moments is not, strictly speaking, true.”

Her book examines the long, sometimes awkward legacy of philosophers’ thinking on romantic love, and compares that with a new subfield in close-relationships research — consensual nonmonogamy, or CNM. While singers and thinkers alike have been riffing on a “one and only” for decades, she argues that space is being made in the cultural conversation to “question the universal norm of monogamous love, just as we previously created space to question the universal norm of hetero love.” These norms are more fluid than they appear: In Jenkins’s lifetime alone same-sex and cross-ethnicity relationships have become common.

Still, CNM faces lots of stigma; even the study of it is stigmatized. Yet in the limited yet rich vein of research out there, the evidence suggests that it’s a style that, in some populations, leads to greater relationship satisfaction than monogamy. In any case, the researchers tell me, the insights into what makes more-than-two relationships work can be applied to any given dyad, given the communicative finesse required when three or more hearts are involved.

In a forthcoming Perspectives in Psychological Science paper, Terri Conley, a University of Michigan psychologist who’s driven the field, defines CNM as “a relational arrangement in which partners agree that it is acceptable to have more than one sexual and/or romantic relationship at the same time.” That’s distinguished from the “polygamy” practiced by some religious groups, where it’s not always clear whether wives can opt out of the relationship.