Dee, it might be easier for you if you really really lower your expectations of getting anything from him. Responsibility, love, care, even basic honesty are beyond him right now. If you don't expect, you won't be let down.
How about concentrating on your beautiful little boy, giving him the best life you can? There's something you can control. He's so lucky to have a Mum who cares for him and can live a substance free life. I'm glad you're going to Nar Anon as the steps will help you recover from your hurt.