My AH is a heroin addict as well. The best piece of advice I have taken away from here is that I NEED to listen to my gut. It has never lied to me, unlike my AH. Yes, I feel crazy all the time. I have been to the point of considering checking myself in somewhere because I can't handle the crazy - but then I pray and focus on what I do know and what I can control - ME!
I always feel like I need my AH to admit it so I can justify that I'm not crazy. That process makes me even more crazy. And boy, can they tell you how crazy you are. So you're AH asked for a divorce - that my friend is manipulation. He is well aware of the love you have for him and will use it against you. I hear it all the time. I wish just one time I had the strength to say sure and give him what he wanted.
Rest assured, you are NOT crazy, you are living WITH crazy. Focus on what you can change and start there. I have never been good at the detachment part - hopefully others will offer some advice. Stay strong and put all the focus on you. Stop searching for what you already know.