I'm really confused about a guy, help?

Me and this guy are close mates. He's really nice to me and we always talk. The other day i liked one of his fb statuses, it was one of those like and i'll tick the boxes ones. Among a few others he put you're hot and you mean something to me, this made me really happy because i kinda like him. I put the same status on and gave him those two things back. One problem, he has a gf. I've never seen them talk or anything though. I would like help because I like him and i'm not sure what to do thanks :)