Oh boy. Don’t bother with boundaries because you won’t set them anyway. Your acting out a fear and that is never going to end well. Once she finds your replacement she’s gonna D you anyway. Your best bet is to call her on her BS see a lawyer and figure out what your options are moving forward. Are you in a no fault state?
Your kids will be fine if they have a dad who is their rock and they will respect you for not compromising your values.
The state I live in is both fault and no-fault. Yes, there is a certain fear there - mostly for what will become of my kids. I am going to get a consult.