You need to remember that you are dealing with an addict. No amount of reasoning will make a bit of difference. MM needs to reach her bottom and she hasn't yet.
She gets a fix each time she interacts with ExBF. It's every bit as strong as heroin or booze or whatever...it's her drug. She is protecting her drug and you can't reason someone out of drug use.
MM, my question to you..."Why are you here?"
"You know, it's times like these when I realize what a superhero I am." Tony Stark/Iron Man
“Focus on what you can do, then do it with all your heart.” Lois Wilson