First off, I don't know if this helps any, but I wanted to say that at least to me it does make a certain kind of sense to stick around in bad relationships. That doesn't mean you should stick around, but I just wanted to acknowledge that it's not as easy as saying no to some food you don't like. The wish to belong, to have a family, to have a group, is very strong. It goes to the very core of our most basic survival instincts and it's scary to take the plunge of leaving what you have. At least you're not alone where you are, you have a context and a place. So for what it's worth, at least to some random dude on the net, staying around even when it's bad is understandable.

With that said, you have the right to demand respect for who you are. When you do something nice for someone else, you have the right to a sincere "Thank you". In particular, you have the right to draw boundaries on what kind of treatment is acceptable to you. You have needs too and this is one of them. You are not obliged to be someone elses punching bag your whole life. Everyone has ups and downs and sometimes we have to take a few hits for the people we love and care about. But if it comes to a point where it's wearing you down and poisoning your life, then you are the final arbiter of when enough is enough. Maybe you can't just walk away, and it speaks alot to your character that you're unwilling to just abandon him. But maybe it's time to look at options? Is there some way that you could get relief and assistance? From what you're describing, it seems to me that you're at the point where you can say "Either A and B changes to C and D, or I'm out". I don't know if any of this helps you at all, but I at least wanted to try and give you a little encouragement by saying that you'd be completely justified doing so!