well it seems like you don't feel that much attraction to him... so for now, I think it's best for you to keep it away from your friend and just talk to him about the issue if you feel uncomfortable with it... otherwise just try to act like it didn't happen. I think that will work out the best for all of you.
as for the bad at relationships, I can't think of anything helpful, since I'm the exact opposite of your case. but I think that's fairly normal to get bored with relationships..
hope I helped any.