First off, the vast, vast majority of people aren't going to react with disgusted surprise at being told someone likes them (or used to like them). Most people have better manners than that, and I would hope you are focusing your interests on people who are at least socially savvy enough to not be jerks in that area. I wouldn't put too much stock in that reaction.
Same thing with the arm thing, particularly when he was putting his arm around two of you at the same time. It is lovely to get personal physical contact - you like it, he likes it, I like it - most people do.
Continue to be your lovely and friendly self. With him, with your female friends, with everyone. If something happens, great (and you can initiate contact, you know)! And if nothing happens, then you will have been kind and pleasant and have nothing to regret.