Other posts mention Al-anon and Nar-anon as sources of support for family members of addicts. I've attended a few Al-anon meetings, and can recommend them, but most of my experience has been with Nar-anon. I can't say enough about how helpful meetings and readings have been to me. I have to admit that at first I just dabbled- went to some meetings but didn't really commit myself- but this summer after my son relapsed I got serious. I now have a sponsor - we had our first one-on-one meeting yesterday and have committed to regular phone calls to check in as well as a weekly in-person discussion. I think having a sponsor and working the steps under her guidance will be so helpful.
One of the hardest things for me was to reach out for help- I felt so much guilt and shame about my son being an addict- but there are so many parents in the same boat. It helps knowing that I am not alone.