I agree with Mr.Ben on most of his answer, but not the last line.
The key is communication.
If cheating is a deal breaker for you then you should tell him that, after, of course, promising you would never do that to him.
My husband and I have both been cheated on in previous relationships. We've discussed our ground rules about adultery.
We both know where the line is drawn in the sand and we've both promised never to cross it.
In the unlikely event either of us wanted to stray, we promised to break it off first out of mutual respect.
It works for us. We've both been hit on. We talk to each other about it and reassure each other that our love is safe.
As for Mr. Ben's last line that if you get cheated on it must be something you're doing...he wasn't clear what he meant by that. I can't agree unless I know exactly what he means.
If you want to make it last you need to let him know exactly what your fears and expectations are. Remember that he can't read your mind and you can't read his. Talk, talk, talk.