I do not believe anyone is ever "the" problem in a breakup. But, your relationship sounds like it has more problems than are surmountable at this time? You speak of your angst but I don't really hear any you feel is coming from him, it sounds like you feel it is almost a "trick", his apologizing and knowing what words to say to get you back, etc. That has red flags for me, that you go back to words, and then he acts the same?