It's your job to be their shield from all of this.
As hard as it is, you can't let them see you down and suffering and if your children don't motivate you to change, then I have no idea what will.
If you stay on this path of constantly getting caught up in your w's drama you will continue you to feel beat down, drain and depressed. One way or another I hope you will learn.
Much of the advice that has been given to you seems to fall on deaf ears. I could have copied and pasted the same advice given to you months ago and it still would apply here.
When are you going to do something different?
I'm sorry if this upsets you, but I care enough about you that it pains me to see you struggle.