It seems that you and I are in the same boat on the same crappy river. Ugghh... it is not a peaceful ride, I know.
I blame myself too... I wanted to be the impetus for his change. I wanted my leaving the relationship to be too much for him to bear causing him to breakdown and do whatever it took to make me stay... I think he probably just smoked a bowl instead. I try to explain all the rational reasons to myself about why that did not happen but my heart refuses to understand. I look forward to the passing of time so that I may truly gain some much needed perspective.
However, in the now, I am also longing for a phone call, another e-mail (they are our only communication and they are few and far between), some sign that life is sour without me. That he realizes the error of his ways and he is ready to step up to the plate. That has actually happened before... we had been apart for a LONG time and he approached me with apologies and the grand gesture I had been dreaming about.
I suspect, given the nature of your relationship, that you may have been on and off as well. In another post you mention having this kind of hope and I think that it is okay to keep hope alive.
Having said that, do not delude yourself with illusions about who he is or might have become overnight. I just mean that if you guys have a past that includes being together, separating and then coming back together, you have every reason to believe that history may repeat itself. It may seem as though that hope may prove to be dangerous as it can soothe you one moment and then disappoint you the next if things don't play out the way you would like them to. Just don't beat yourself up for holding onto hope for someone who you care about and love... it is natural and it just means that you love him deeply. If it does happen, just be honest with yourself about what you are willing to deal with. The suffering that you are enduring right now (without him) is not for nothing so draw your boundaries and commit to them.