Leave the cheater to his or her cheating ways and find someone who will not waste your precious time.Find someone like yourself who is not a cheater and be happy.I'm going to.
Sorry about your painful situation. I'd just point out, if it was as simple as "find someone who will not cheat" you'd have done this in the first place (as would everyone). People have personality issues, problems, do bad things etc. There's a mix of good and bad in everyone (including you and I)....and I don't think it's ever possible to enter a relationship without the risk of pain.