Kelly Gosalves takes a look at a new study in The Archives of Sexual Behavior that compares relationship satisfaction measures between people who are practicing consensual non-monogamy from those who are practicing non-consensual non-monogamy (cheaters). We probably didn't need a science to tell us that nobody likes cheaters and that cheating makes for unhappy couples. But we did need science to distinguish the mutually desired and consented to sexual activities of couples from, well, cheaters. Thanks science! It's about time.