I concur that what she is doing is emotional blackmail. She is manipulating you if that makes it easier to understand. I'm sorry you are having such a tough time. She broke up with you multiple times but turns on the waterworks when you try to move on? I agree she has issues. Please break it off in order to protect your own well being. You don't need to come up with a reason for breaking up. You could simply say it's not working out.

I hope you can break this off without feeling guilty and move on. Best wishes.