I can't believe how many people think this is okay.
I know a lot of people who have tried to continue a relationship after cheating, tried to forgive. None of them could really get over it and all the relationships ended up ending.
If he couldn't control himself then, what makes him think he can control himself in the future?
Kisses do not just "happen." There was a flirtation and an escalation. He made decisions each step of the way. I'm gonna say there's a 50% chance at least that more than kissing happened too and he's just too scared to tell you. How often does a drunken hookup end up with *just* kissing?
I'm not saying you *have* to break up with him. But ask yourself honestly - can you really forgive him and fully trust him going forward? Because if you can't, you should end it.