A very sad story, indeed. I am no expert but from everything that I have read / researched, this completely follows the typical pattern of an abusive relationship. Right from the promises of change, going to therapy, to the repeating patterns of abuse .. and now, for you, in terms of guilt and self blame. I totally believe in giving people a fair chance / shot, but in this case, it sounds like you’ve given about 6 fair chances, with nothing to show for. I totally get it in that you are blaming yourself (I am the same, believe me) … but just know, even if only rationally / intuitively, that you deserve so much more than this.