Something you will discover is that you are not alone. There are all kinds of folks here that understand what you’re going through. Folks from newbie to veteran, and various points in between.
As was mentioned, I think you are in for a rough ride. W’s stated wanting sex with other people, the blaming, the projection, the justification, are all typical wayward spouse behaviour. You cannot talking her out of this. You cannot reason with her to see the light. She has a path she needs to walk, and you (thankfully) were not invited along.
Dig deep. Focus on you and your four kids. Get a Life. And let go W. Give her time and space. Her emotions are all stirred and mixed up. Couple that with addiction and it’s quite a cocktail. She is a lost soul at the moment.
Read. Post. Ask questions. We all require a certain amount of understanding before we can let go. It’s perfectly normal.
Your path is just starting out. Listen to the wisdom of the folks that have gone before. Plenty of this will be counterintuitive. It will feel wrong. Will go against your default behaviour. Realize, everything here is for you. You have to save yourself first. And that gives you your best chance at saving your marriage.
D
Feelings are fleeting. Be better, not bitter. Love the person, forgive the sin.