[valkyrie]

Binks, I think that unless and until two people have "the Talk" where they both agree to be in an exclusive relationship and date only each other, each person is free to do whatever he or she wants. As it seems that you and Chad have not had that conversation, he is, IMHO, doing nothing wrong by hanging out with his ex, and doing whatever else he is doing with her. Just because you and he are hanging out and having fun does not mean that you have a commitment to each other -- unless you have explicity stated that you are not going to see other people. I also don't think that you have any reason to be hating on the ex, unless and until you and Chad are in an exclusive relationship and she is doing something to interfere with that.

I do think it is a problem that he has been disrespectful to you -- inviting you over and then not opening the door, inviting you over when there's another girl there, etc. I also think that it is a big red flag that he doesn't want you hanging out with his friends -- there is usually a reason for this, and it's not a good thing.

If I were in your place, I would think about what I want with this guy -- a relationship, friendship with benefits, someone to hook up with once in a while, or nothing, and then figure out how to make that happen. Good luck, and keep us posted.