He cheated on me but he won't admit it

well how do you know that he cheated? Is it just the girl he slept with or did someone else tell you? I'm not trying to stick up for him but you seem positive that he did it.
Anyway, it's obvious that you love this guy and the fact that you can't get past the thought of him with someone means you really need to talk to him about it. First get him to admit it and then let him know how you feel, both about the situation and about him. I have had friends who went through their significant others cheating and got through it so it's not impossible to do. I hope my advice helped and good luck, I hope everything works out for you.

As hard as it to walk away, it is the best thing to do in my opinion. It sounds like you are never going to be able to trust him again, which I understand completely, and there is no since dragging on the relationship when it will most likely end anyway. I think you did the right thing by walking but you have to be strong and hold your ground. Besides if he really loves you like he thinks he does than he would have never placed himself in a situation for which he would stumble and then lying about it. Hang in there, you are doing the right thing.

These are some hellah run on sentences to read but here goes.

Are you ok with him having one night stands with anything that has a hole? If so, then keep him. If not, then at least let there be some time passing before you even consider whether or not you would want to enter into a relationship again with him.

Remember, he had you for sex, right? So obviously there is something he needs to work out alone before he can be a decent partner for you.

Back away for a while.

Good luck!

I don't want to come off as JUDGMENTAL, but before I continue I think I need to bring something to your attention 2 any girl's attention that may read this. This is not a matter of how '' unattractive '' the girl your guy chose to cheat on you with is . . . Sometimes we lose focus and the fact of the matter is looks or not he CHOSE 2 cheat. Cheating is almost never an easy topic to discuss you have to know that if you chose to give him another chance you are saying that while you forgive him , you have not forgotten. I bring this up because at times we tend to hold on to what we had agreed to let go . . . Forgiving him in a sense would be letting go. You have to be really strong to go through this and you have to realize that although everything has now CHANGED, its up to you to decide if its for the better or worst. I can't sit and tell you what I think you want to hear which is that you should take him back. Tears only go so far and there's no guarantee that he won't give an encore performance. Fact of the matter is love should have kept him from cheating , but it didn't . However love keeps you holding on so what do you do ? If your hell bent on being with this guy by all means do what makes you happy, but if you have any doubts ( which assuming your asked this ? You do) its time to start seeing things for what they may really be. I have been on the receiving end of someone's cheating and it was rough . Lets just hope if you do choose to go back it will be worth it.