KE, thank you for this post. I often think that mothers struggle with the "I didn't cause it" part and spouses/GF/BF struggle with the "I can't cure him" part.
I am also trying to come to terms with guilt. I have done so many things I regret with my AS. I wish I didn't get as angry with him as I did when he came back hostile from weekends with his father. I regret that my little boy had to be so terrified of his father and I was not there to protect him. I regret that I tried to make up for his suffering by spoiling him. I regret that I had temper outbursts when I felt he didn't appreciate what I did for him. I regret that I was so immature when I raised him. I regret that I never managed to salvage our relationship as he grew older.
The truth is, I know I did the best I could under the circumstances. I also know that other people have much worse childhoods and they don't turn to drugs. He may have become an addict even if I was the perfect parent, whatever that is. I also know that I cannot change the past. It is over. I can only trust in God that everything happened and is happening for the greater good of both of us.
Guilt is such a draining, depressing and wasted emotion. I hope that all mothers who suffers from it will be able to let it go.