This has nothing to do with being violent. You are drawing a line in the sand. IMHO you want to stop this interaction now. I still say kicking her out is fine. If you keep letting her indulge in her fantasy, you're not going to have anything left.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.