The biggest issue standing in your progress, IMHO, is that you won't let go of your W. By that, I mean everything you do and say is linked to getting her back. And it's this very thing that causes you to leap when you should change nothing and hold the line.
You have to cut the rope you have tied to her, in order to save yourself......and hopefully, save your children.
Sandi, I wanted to chime in here and say I agree with this 100%.
One of the issues I had was letting my wife go. In the beginning of the separation she told me she should be allowed to make her own mistakes and fail. I told her why would you want to fail? You're in your 40s. Failure should be something you do in your teens and 20s.
In our entire marriage I took care of the finances. She has zero interest in budgeting and didn't even do the book keeping for her own business. I had to do all of that especially when tax season came round. She also did no maintenance on her car and would only change the oil or top it up when the oil light came on. These things didn't interest her until they became a problem, i.e. the car needed fixing.
So being a typical guy who likes to fix things and believes prevention is better than cure I would remind her to top her car fluids up even when she moved out last month. Because she picks my kids up and drops them off I didn't want to get that phone call that she can't make it because her car broke down due to her negligence. I didn't want to see her struggle with a broken car, but she hated it. She said I was "controlling" but all I was trying to do was take preventative action. I even told her to set alarms on her phone to remind her to check the oil as it leaked and needed topping up once a week.
I also got on her case about giving my daughter medication as she would forget. Again, I'm called controlling. Now I just have to trust that she does it. This particular medication has to be given to my daughter three times a day.
Am I being controlling by reminding her? Or is it better to let her fail because of her negligence.