Recovery from codependency is difficult at best. You are making some strides, and it will take time for you to understand the cause and effect of loving an addict.
Firstly, you must remember he will always be an addict, it's just a matter of whether he is active or not....that's it...this is a disease that has no cure.
Secondly, you can either be proactive or reactive to his behavior, if you keep getting dragged back in, limit your conversations with him...take a break, it is not the end of the world.
Lastly, feed your subconcious mind with the thought of detaching, every night before you go to sleep say "I will detach from XYZ" eventually your concious mind will believe it and things will get easier.
Detaching doesn't mean physically running away, it is a mindset that keeps your bounderies in place.
I still think you are over analyzing this detaching process, rather than trying to figure it out, take some more steps to put the wheels into motion.
My Best,
Dolly