Dating a cheater...

How many of y'all are currently still in a long term relationship with someone who's cheated on you? I need advice. It's been 7 months since, we've been together for 9. I feel like I'm investing in a relationship that's not going to last. He's everything I've ever wanted, until he screwed up. I always said I'd leave anyone who ever did that to me, but it's so much different when you're actually there.  I've never had to deal with this before, need some advice.