A new study shows that in 40 percent of heterosexual couples ages 18 to 25 who discussed monogamy, one partner said the couple agreed to be sexually exclusive while the other partner said there was no such agreement, according to a statement by Oregon State University (OSU), which conducted the study published in the Journal of Sex Research. The couples surveyed included both married and non-married couples. The study also found that among couples in which both partners agreed to monogamy, nearly 30 percent had sex with at least one partner outside of the relationship. The study, researchers noted, shows that couples often miscommunicate about monogamy and as a result misjudge their partner's sexual risk-taking.

To read the OSU statement, click here.