Help: what should I think about my relationship?

Just be careful because the way he treats other people may be the way he treats you some day. You could talk to him about it and ask him why he seems so defensive with other people and see what he has to say. I think with people like that it is only a matter of time until they turn the way they treat other people on to the person they are seeing. Could be that this is his true colors. He is being good to you to keep you on his good side. Can you imagine if you ever made him really angry? Might be scary!