I am of the belief that things happen when they are meant to happen and that is usually when we are more ready/prepared for it.
I think you’ve learned a lot about addiction in this past month or so and I hope you can accept that his addiction is not personal towards you. His behavior is that of an active addict and someone with a long history of it. The chance he will change into the someone you think he can be, are slim. I think you are near accepting that, and as hurtful as that may feel, the truth is what sets you free. Holding onto a fantasy life/relationship keeps the heart from healing.
I think one day you will come to understand that you were having a much different relationship with him then he was having with you. You’ve reached another stage in your grieving of this relationship, the hard to accept stage. The stage where truth and reality become clear and all of that hope begins to drift away.
I am sorry you are hurting again, I know it really does stink to love an addict.