You sound so centered. I think once one recognizes drama for exactly what it is it becomes easier to deal with.
In my case, it's becoming much easier for me to move forward the more I distinguish his path as his path, and my path as my path. More to the point: My path as My path regardless of his path. In other words. "God bless you, honey. I wish you well, but I'm getting out of this rabbit hole."
It's may be just a bit more of a spiritual detachment than the one usually referred to. I'm not quite sure how to explain it. I do think, however, that in wrapping my own head around the necessity of the breakup, the fact that I was unable to save him, the fact that he didn't want me to save him, the fact that my ability to parent my amazing, beautiful, spectacular, gift of a daughter was drowning in the quicksand of his addiction. Made it easier for me to articulate what was going on to others. Once I was clear with myself I could make it clear to others. Maybe this will be the case for you as well.
You already sound like you're clear on the "why's" and "wherefore's". Just try to remember to be good to yourself, and take it one day at a time. Maybe check out Alanon if you haven't already.