tool

someone who constantly cheats on their significant other, can be male or female

my friend was dating this guy, and one night he and my friend's best friend were hanging out and ended up having sex. my friend broke up with him when she found out and then he and the best friend started dating. until he cough the best friend making out with is best friend in the school library. the guy and the best friend broke up

both the best friend and guy are tools