Adultery Swim

I started seeing a guy whose previous relationship ended because he cheated. He insists he really learned his lesson and would never do it again. Should I trust him, or should I go by that line, "once a cheater, always a cheater"?

--Worried

People in relationships do develop little traditions -- like coming home every night and checking the closet for their boyfriend's sex partners. The question is, does the skeleton that your boyfriend's yanked out of the closet point to a heavily populated closet in your collective future? This is ultimately a question of whether he's a cheater -- a person psychologically "wired" to be prone to cheating -- or a person who once cheated. There is a distinction. Sometimes, somebody cheats just to see what it's like to walk on the bad boy/bad girl side -- the (heh) Socio Path. And sometimes, in the moment (SEXXXXX!), somebody who's generally considerate puts their partner's feelings on "ignore." However, evolutionary psychologists David Buss and Todd Shackelford found there seems to be a cheater personality -- a trio of personality traits common to people prone to infidelity: narcissism, low conscientiousness, and "psychoticism." That last one -- psychoticism -- suggests an ax-killing hobby, but it's actually researcher-ese for a combination of impulsivity, unreliability, and an inability to delay gratification. Narcissism, of course, is the "Me! Me! Me!" personality trait, reflected in self-absorption, self-importance, exploitativeness, and an empty well in the empathy department. Low conscientiousness is the personality trait of the inconsiderate, reflecting disorganization, poor impulse control, and an inability to delay gratification. Yet another factor is a personality trait that psychologist Marvin Zuckerman named "sensation-seeking." People "high in sensation seeking" crave a variety of new, complex, and intense sensations and experiences and will take physical and social risks to get them. Talk is cheap -- especially for the ethically sketchy, the morally underfunded. Look at the guy's behavior and thinking -- in your brief past and in the weeks and months to come. See whether it adds up to good character or reflects the cheater personality markers. Sometimes cheaters change, but personality traits have a substantial genetic component, so cheaters mostly just change who they're cheating with. If your boyfriend's moral compass is secretly set on Booty Call North, you're setting yourself up for many joyful years of checking his shirts for some hussy's self tanner and trying really hard to believe that he only goes to strip clubs for the music. ... For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.