I lived with a man who blamed me for many years and there is completely no good reason, none, zilch, to live with a person who thinks that you ruined his life.

The time you spend being puzzled over what seems to be inconsistent behavior and the general sense of inconsistency in him that one gets from reading your posts would be better spent... literally, doing ANYTHING else but analyze the inconsistencies in him. Just leave him and consider him a puzzle that you will never solve. Do it really matter if you move on and eventually get into other relationships whether you can then say that "Yes, I, Monica, was finally able to answer the question "What REALLY REALLY REALLY was going on in his admittedly weird mind?"

Further, you ask: "If it's more likely that he has problems, does that justify the way he verbally & mentally abused me these months?"

The answer to this question is completely irrelevant. The relevant part is that if someone abuses you, either because he is mean, or because some events of grandiose proportions happened to him in the past and affected a deep wound in his psyche that he is now trying to cover up with bandages, and those bandages just happen to be his abusing you verbally and mentally, then you stop letting the person abuse you by severing your connection with him.