NoCode,
I have recently simply "decided" not to respond to stbxh's venom. I prefer not to defend myself when he lays into me about what a bad wife I was. I have told him not to start any R talk and I do not either. I do not "Bible thump" him (his words) because it is his walk with God and not mine.

Teach your sons what you want them to learn from you about morals and integrity. Your teachings of what is right and wrong can certainly supercede your stbxw's version of what is sin and what is not. Worry about you and your sons.. not her.. Don't respond to her..