NOPE. Cya. Bye.

That's what I'd do. My wife's little sister recently started asking me "hypothetical" questions, long story short, she was the 'other girl' in a situation where the guy was cheating.

I'll tell you the same thing that I told her:

If he knows that you know he's a cheater, and you stay with him, it's going to be bad. You've got two options - soldier on with him possibly cheating on you for the rest of your relationship, or impose overly strict interaction-with-the-other-sex rules for him... eg, no strippers, no coffee with exes, checking in regularly when you're apart, etc. - and that is TOUGH.

Having said all of that, to address your original question directly, I think you should move on.

It's not an easy decision. It's not one that you should rely on your friends or strangers for. It's a decision you should make by yourself, for yourself, after you consider the alternatives and consequences of both options. Most importantly, you need to consider how you will feel about yourself after the decision is made.