You probably took him back because, as you said, you felt obligated to keep trying because HE was (allegedly) trying. It's a common theme here - "well, he's in rehab, I can't just dump him now..." (even though he's cheated on me, spent all our money, abused me and the kids, etc etc etc)
Lighten up on yourself and let yourself look forward to the future. It'll be so much more peaceful, healthy, and happy
