1. You bring home the same amount of money. A recent study from the American Sociological review showed that partners were less likely to cheat if they were in the same (or similar) income brackets. Men were more likely to cheat if they made a lot more money than their partner, and they were most likely to cheat if they made a lot less. So if you two have similar paychecks, you've got statistics on your side.
2. He's from the Midwest. According to this poll, Midwesterners are just too well-mannered to cheat on their partners.
3. His friends are also faithful. People are more likely to cheat if their friends are also cheaters, according to M. Gary Newman, author of The Truth About Cheating. If his friends are trustworthy, it's likely he's trustworthy too.
4. He's really into Pantera. Yeah, according to this survey conducted by the Mirror (so, questionable), heavy metal listeners are apparently the least likely to cheat.
5. He comes from a big family. A survey from adult meet-up site Seeking Arrangements shows that cheaters are usually only children. Ask if he has a sister.