Welcome, Litehorse. I'm sorry you find yourself in this place, but you should be so grateful that you've stumbled onto this forum. Please keep coming back and you will find all the support you want and need. I only wish you would have found us a long time ago... it sounds as though you've been struggling for a while.
I am very familiar with that feeling of discouragement. I am the parent of an addict also and I remember coming here to SR and reading, reading, reading. Frankly, I was shocked by the reality that was here before me. I came to understand clearly that for most (not all) addiction is a lifelong struggle... rehab is just a first step on a very, very long path. The most IMPORTANT LESSON I've learned in the last couple of years is that I deserve a life of serenity. His life is not my life. His addiction is not my addiction. His problems are not my problems. I am not responsible for his choices!! So I let go. And letting go has been key to keeping my sanity. It's hard but of all my choices, it was by far the best option for all concerned.
As I said, please keep coming back. We're here for you.