Look at the big picture. Divorce is emotionally and financially devastating. It's a lose/lose but a reality.
If you want to teach your kids how to maintain a toxic relationship, keep doing what you're doing with their mom.
If you want to get healthy, maintain your boundaries. Her personal life is none of your business nor should it be of any interest.
No need to be perfect. No need to be a victim. It is what it is.
Get out of the clouds, put your feet on the ground, accept the reality of what 'is'. If you can't let her go, tell her.. "I'm so enmeshed with you I'm only complete when I can insult you."
She's the monkey. On your back. Or do you take turns being the organ grinder?
