Never be on the defensive with her, always be on the offensive. Regardless of whatever she says, if she's late with rent or payments or whatever - get a lawyer to write a letter and ask her for interest and so on. Just hit her with every single little attack you can. Not as a revenge, but to keep her at distance. She will probably pretend to be a victim but that won't help because you will only demand what is rightfully yours and will not skip anything she owes you.
if she breaks something, call a repairman, and send her the bill. If she doesn't pay, send her to a lawyer, collection agency, whatever.
If she wants anything, make her sign a paper that she really wants it so you have it in writing.
No trust, no slack, just cold hard facts and make her responsible for her actions. She won't accept that, but you will be happier and will find it easier to separate from her.
If you don't do that, she will be on the offensive, and even if it may seem silly, she could get someone who is of similar psychological profile to get on her side, and that someone may work at social services or who knows where and then you have a real problem. She won't do that while trying to defend herself; and even if she does, your strategy is to only ask for things she owes you, in the harshest possible (but LEGAL) way.