He said, he cheated, because he didn't feel he could talk to you about certain sexual needs?

That, doesn't display a person, ready to commit to a monogamous relationship, never mind marriage. In a marriage, the ability to communicate, is huge.

Have you considered pre-marital counseling? To help you get past, the infidelity, if staying is what you desire?

Although, it's one of those things, give them an inch, they take a mile. Let him 'get away' with it, this time, and after a lifetime together, how many times, will it happen, again?

Resolving this now, before you are bound by a legal contract and children, isn't a bad idea...