You've got to dump him. You shouldn't have dated him in the first place, because dating non-Christians gets people into a spot like you've gotten into. Yeah, it'll be painful, because pain comes with doing stupid things, but you'll feel better after a while, and God will send you someone better who *is* a Christian. Let me repeat...God *will* send you somebody better who is a Christian...it just might take some time, so you have to be patient. Maybe this guy will eventually become a Christian, but you probably aren't a very effective missionary when his tongue is down your throat. Also, if you were to have kids with him by chance, you don't want to chance your kids busting hells gates wide open along with their dad because they didn't have a Christian father.
Also, you may think that you've broken the cycle of lust & sin, etc., but I doubt that you'll be able to keep it up. Yeah, you've got resolve right now, but give it a few weeks for your hormones to build up again, and you'll most likely give in. In this case, most likely means 99.999% sure. Be honest with yourself and you'll know I'm telling the truth.
Of course, if you're like most other folks who get into relationships with non-Christians on this forum, you'll ignore people's advice to break up with him. Just call me Cassandra, I guess.