Have you looked into Narcotics Anonymous? There is help available for non-addicted family members too.
Why do you think you would stay? Not because I always have, but what's driving you, what's the pay off? It isn't an answer you need to post. You do need to really think about it though.
The only way I know to stick to your guns is to put on your Nike's. Just do it. I would offer that if you aren't sure of a line you're drawing in the sand, don't put it there. However, addictions are a different animal.
Is this really what you want for yourself? Is this all you think you deserve?
If you haven't seen a counselor, I would recommend it. A professional can help you sort it out.
