I really couldn't answer your question. But if you think he was using I'm sure he was. I was married to an alcoholic drug addict for 29 years. It has been 4 months since I left and not even a month since the divorce was final. Yes, he has moved on. I am still hurting and trying to make since of my life. No I don't want him back but I would like some answers that I'm sure I will never get. I hope it helps to know that you are not alone. Hope you heal quickly. It takes a strong woman to leave. Stay strong. Your future is ahead of you, but you can't find it if you keep looking back.

i've read it takes about two years, but after 6 months things can get a little better. i'm glad you left for your son's benefit. i would have had to do the same if i'd had a child.
yeah it's losing someone you really cared about and felt right with, but sometimes you have to do the hard stuff and you're doing the best thing for your son, and later you amy realize it was the best for you.
it really hurts, the sorrow, loneliness, loss of the life you had, but you'll get through it. you can go on and build a new life, and it will be better than what you had.