YES. Absolutely, positively.

You said yourself that she's admitted she lies constantly, is well-versed in manipulation and pushing emotional buttons (and apparently looks up information to find more to push -- don't kid yourself why she studies these things.) And that it's hard to trust her.

There's a good reason for that. Because she CANNOT be trusted! You want to believe. This is a sociopathic goldmine. That you fear not believing her? She knows this already. It is The Game. And she's sitting in the driver's seat. Perhaps you think that being the "good guy" will keep you from being used to meet her ends. You will not be exempted. No one is.

Sorry. Truly, I don't mean to be harsh, but I do need to be direct. I'm prone to being a doormat too and relate very much to things you say. I've seen firsthand how our empathy, doubt and fear endanger us. And they are VERY good actors. We want so badly to believe, to be the good guy. To us, it is a strength, a goodness. To sociopathic thinking, it is a weakness to be exploited.

Good advice on boundaries. They are absolutely critical. And please, if nothing else, heed lolagrace's advice. Do NOT put yourself in he said/she said situations. No overnights, no long stays, avoid one on one. All it would take is one contrived incident to turn your world upside down. Remember. You are not exempt and they are very good actors (and from my experience lean heavily on the pity/victim card as it is highly sucessful).

I've never posted in this part of the forums. Your situation speaks to me THAT strongly. Please protect yourself. Boundaries. Boundaries. Boundaries. Wishing much strength for you.