I'd like to make a subtle point by rewording your conclusion to one I made about myself a while ago:
Conclusion? If I dont' keep her toxic emotional drama out of my life... .it could cost me my sanity.
It is a harder job to keep a person's emotional crap out of your life than keep a person out of your life.
You can make a clean cut of everything.
You can keep their crap after you stop seeing them.
You can stay with them and not pick up their crap anymore.