Confused...

I slept with this guy I have been hanging out with. We get along great and I think I might like him. After we had sex, we sat on his couch watching Netflix and he had his arm around me and everything. However when I told him not to tell anyone about what happened, he said he totally understood but then stopped putting his arm around me. Does this mean he might like me more than I thought? The catch, though, is that I have a boyfriend and this guy knows I have a boyfriend. I've even talked to him about my relationship with this other guy. (I know this is extremely wrong, and I've already had a long lecture from my friends... But is there anyone who can possibly explain what he might be feeling?)