I found my detachment a couple of ways. Deeply reading and re-reading "Under the Influence" helped me really understand the disease. That no other human is sustaining the brain damage but the addict...so was not mine to grapple with. The best thing I got was right here in this forum too, from a recovering alcoholic:
"As an alcoholic, I cannot understand how my behavior hurt my family. As a family member, you cannot understand what it feels like to be an addict. Let me explain it this way: If you were in a pool of water and something pushed your head under the water, you would fight with every ounce of strength and resolve you had to get to the surface. While in this struggle, you would not have a thought about your spouse, your job, your kids or even your own well being. That's what being an alcoholic feels like"
Oh my gosh. Hearing that...my heart cracked open and I was flooded with compassion. What a nightmare way to feel and live. I imagined what that struggle must feel like every day. How the smallest things would make me want to find refuge from it. The very second I could find a small bit of compassion, I began to detach. Being able to actually try to feel what he may be experiencing was the key to my own peace of mind. Of COURSE I did not cause it, nor could I cure it, I could only look for my own way to peace again.
Finding compassion first, detachment follows closely behind, in my experience.