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Next, back to the sitch at hand. One of the biggest reason that you cannot seem to get past the anger leaps out at me in your last two sentences. You just said that you understand and accept that this is HIS drama. It is his drama, pain, problem and confusion that is all that's going on now. People in this kind of pain and self-involvement don't have time to worry about others, and they don't do things to others. When you wonder about how he can be so cruel to YOU, or how he treats YOU with disrespect, you are taking all of his actions much too personally. He is acting selfishly and trying to escape his own confusion and pain. He really has very little interest in you right now, and as such is doing nothing to you. You personally take this "nothing" as cruelty and disrespect. If you can detach from taking his actions personally, you will be able to shed your anger more easily. You will be able to allow him to live and suffer in his own misery and stop making yourself angry and crazy. You will also stop being a target for him to blame for his misery and force him to look at his actions and maybe consider how it is HIS actions, not yours, that are causing his confusion and pain. He must come to this conclusion himself. You can do nothing to bring him to that awareness, other than avoid placing yourself in his sights so he can blame you for HIS problems.
I know that what I'm saying may sound like total insanity to you. But you are in an insane situation. And the more you continue to do the same things trying to solve the problems, the more you contribute to the insanity. I don't pretend that what I am suggesting is easy. But I do ask that you think about it and try to see if you can do it and then notice what happens, first of all to your peace of mind, and secondly to his reactions.