I am really sorry that you have to go through this. I know from personal experience how much cheating hurts. I have never felt anything more painful in my whole life. Please don't feel like I am telling you what to do but from my own personal experience, once a cheater always a cheater and you will probably never gain the trust back in your relationship. Also, if he does love you as much as he claims to, he would be doing everything in his power to keep you.
Stay strong sweetie.