tanzanite
My heart goes out to you. It is doubly hard to let go when there is a child involved.
For me, prayer and working on turning things over to my HP minute by minute helps.
It also helped me to do a lot of spiritual reading, go to Nar anon family meetings and seek some counseling for myself.
I also think for me that separating the pain I felt at watching my addicted niece destroy her life was different than being caught up in her drama. So I concentrated on learning to feel my pain and let it go versus trying to control her choices. Sounds like you've done a good job with that. I think for me the hard part is that as long as my addict is not in recovery, and as long as I love her - even though I let go, it still hurts.
I've also done a lot of reading and thinking about the value of suffering - my addict's and mine, and the lessons there are in the acceptance of it.
Prayers that you can find some peace amid this struggkle until it gets better...