I need relationship advice.?

You did good by dumping him but I think if he doesn't like Jess. You should chase back after him and find out his current feelings about you after your break up.Then try to start back a relation ship with him. Im a guy and think we do have a habit of flirting with girls while in a relationship but that just means maybe that the girlfriend is getting boring and needs to step in to his life more and talk and flirt with him more. So when you get back together you can talk more so he doesn't have the chance to flirt with other girls.You can't spent too much time with you gf/bf and you cant spend to less time With them or you will loose interest and break up.Your just not going to have a perfect relation ship so worry less.