I was going to reply but I thought it's best not to especially after what she called me. The way she feels about me is the way I feel about her.
Please don't acknowledge her remarks.
For all you know, she has fake accounts watching your FB.
She tells you how wrong you are, but she thinks it's perfectly fine to put a picture of her and OM up for the world to see. I guarantee you she would be ready to file papers if she heard you even talked to another woman. Just like she responded when your mother kept the kids while you were at work that time.
Things will never be equal in her world. What is fine for her to do.....does not apply to you, in her way of thinking.
The best way to handle it is to stop looking at her FB and don't reply to her messages. Don't give her the satisfaction that it bothers you....and certainly not let her know you went under a false name to take a look.
You are better, higher, and deserve much more.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!