Ill chime in on this because I was married to someone just like her and did not find out about her till about a year and a half into it. It was after our son was born that her true side came out after we had a spat and I left the house to let things cool off. When I came home I came in through the kitchen and there lying on the table was a Barbie Doll with no head on it. I thought it was a little weird but went on to the bathroom to relive myself.
When I got there I was taking care off myself when I look over to the sink full of water and there was the head to the floating in it. So I went in to ask her why the hell was up with the doll head. And what she said and the way she said it scared the hell out me. She Said ITS YOU and it sounded like some demon out of a movie.
But the best this I can tell you is if she showed you this side of her it's there so trust your first gut feelings because they are usually the right one's.