oh he doesn't blame anyone else, that's obvious from his conversations. I think what bothers him is after some self-reflection he realizes what kind of person he is. Probably not enough to change himself for the better, but who knows.
I agree with this. It's pretty clear IMO that Ian realizes that he treated Mina terribly and feels kind of bad about it, and at some level he understands that their relationship was never going to last because he was treating her bad.
I think there's also a certain amount of self-hate and/or self-sabotage going on, whether or not Ian is aware of it. His dialog reads to me like he feels, somewhere deep inside, that Mina deserves better than him, so he lies and cheats and pushes her away. But he also recognizes how good she is, and somewhere inside him he's mourning not only their relationship, but the fact that he is the one who destroyed it because Mina was too good for him. Hence Edwin's mention of self-fulfilling prophecy.