AbandonJ
Sorry to hear about your situation.
You were good enough and have no part in being blamed for the breakdown of your marriage.
Reality is he chose his path. Part of this will be down to the drugs and alcohol. This will have severely numbed his emotions. An addict will always choose the path of least resistance. A normal family life doesn’t align itself well with an addicts way of being.
Now, I can sense the resentment to this other woman. This will be hard to read, I don’t believe she’s got any blame in this. Your husband chose his own path, she was there as the path of least resistance. She’d have allowed and maybe even encouraged this way of behaviour with no recourse back to him so he doesn’t have to take any responsibility.
Now you’re at a crossroads. You either live life with yesterdays baggage forever hanging over you or you look forward to a fresh start with limitless opportunities. Resentment will only have negative consequences and won’t allow you to grow as an individual. If anything you’ll become the shadow of your mere self as these negative emotions eat away at you.
I wish you well