You are strong! Being strong does not necessarily lessen the pain, but IMHO, your inner courage rises up to face it and give you the ability to deal with it. Courage is a mental attitude that supports your actions in spite of your fear.
It might be best if you stayed away for a few days, and not communicate with her. Let her try to blow up your phone, or block her number. If she can reach you, she'll pull you into another round of yada yada that has no profit for you or the M.
She needs no explainations. She knows what she's done.
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!
