Where to start? Well, have a read of the stickied posts at the top of the forum. There is a wealth of information there. Reading these posts helped me see that my situation wasn't unique. I wasn't alone in this any more! I'd also recommend getting and reading a copy of Co dependent No More by Melody Beattie. It's a really powerful, life changing book. A must read for anyone with an addict in their life.
I'm so glad you found this forum - it has helped me so much, I'm sure it will help you too!