Wow...neverending...it has been a long time indeed!
People do find sobriety and recover. Look at the many that visit this board who have recovered from addiction. But remember...they will be the first to tell you that there are no guarantees. Relapse is a reality with addicts.
I think if you are trying to make a decision you need to question how comfortable you would be giving it a 3rd try after having been through all you've been through. How much do you trust him? Are there still things that bother you about his behavior? Has he proven his reliability?
I'm just posing questions that I would pose to myself. My divorce was final in June of 2007. Two months later is when he decided it was time and he had hit his bottom. So now he's sober and recovering. I say good for him...it's what i always wanted...to see him living life not ruled by a substance. i keep in close contact with him, practically everyday, on a purely friendly non-romantic level. It's nice to watch him become a "man". He wants to reconcile but what keeps me grounded are reminders of what used to be.