(((((Frog))))) No great words, I'm sorry. I think it is always the most scary in anticipation of a major change and the hardest part is just getting to the point that it is done. All I can say is you are right...you are doing the very best thing possible for your family. You are protecting your children from the insanity and giving them a chance to live in a safe and peaceful environment. That's what it's all about, right?
Divorce does not mean you have to stop loving him. It truly is the act of detaching with love in this situation. Perhaps it would bring some comfort to remind yourself that there is always hope and perhaps someday he will get it and you will see the man you love completely, not just hidden behind the crazy active addiction ways.
It always helps me in situations like this to stay in today, to not think about future-tripping; to remind myself I can get through this day and this day only and find something to be grateful for.
Sending lots of prayers to you and your family. Hugs