Was it wrong to take advantage of my roomie while he was drunk?

I'm a 44 year old bi-guy who shares an apartment a 20 year old straight guy. We've been staying together for about a year now. He thinks I'm straight and I think he's hot. The other night we had a couple of beers together and had a really great time. He's not a regular drinker like myself (hehe), so I sort of took advantage of him. He didn't resist and actually seemed to enjoy it. The next morning he acted like nothing ever happened. I really want to pursue our relationship. How do I speak to him about it?