Hi LifelongLoner, just a P.S. here...

If this helps at all, I've asked a question to a therapist on PC linked down below. You can see my name, Ennie on "Asked by." I sympathize and empathize with you as I too have witnessed a ridiculous amount of persistence from a pathological person.

How Can I Get a Narcissist to Let Me Go Emotionally ? - Ask the Therapist