Part of the reason for the difference may be that consensually nonmonogamous people often explicitly stipulate that outside sex is okay, as long as it is safe. Cheaters were also more likely than consensually nonmonogamous people to be drunk or on drugs during their outside encounters. Finally, skipping safe sex may be a way for cheaters to rationalize their behavior, Moors said.
"If they had gone out and gotten protection then it might have seemed more planned," she said. "It might have been like, 'Maybe I shouldn't be cheating on my partner if I have to walk to CVS to pick up condoms.'"
There are many open questions left about polyamory and other nonmonogamous arrangements, but research is picking up, Holmes said. This weekend, the first International Academic Polyamory Conference is being held in Berkeley, Calif. The Internet has likely boosted interest in polyamory, said Sheff, who is working on a book about polyamorous families.
"The Internet has revolutionized things for sexual minorities in general," Sheff told LiveScience. "It offers people a way to find out about it, and it offers people a way to find partners."
Polyamory is complex enough and time-consuming enough that it will likely never overshadow serial monogamy, Sheff said. Nonexclusive hook-up culture has young people negotiating consensual nonmonogamy like never before, she said, and people are increasingly thinking of relationships as build-it-yourself rather than prepackaged.
"I think polyamory will co-exist as a less popular option" than monogamy, Sheff said. "Or people will phase in and out of it at different times in their lives."
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