What kind of treatment does my fiance need for bipolar disorder?

Hi doctor,

My fiance and I have been together for five years, and she has been taking Lithium for bipolar disorder. We are living in an apartment, and she accuses me of being a cheater. She has no reasoning other than that I am communicating with people upstairs through the walls. There are men and women living upstairs, and when you hear them walking or making any kind of noise, she says I am a cheater. When I type or click anything or cough or clear my throat or even breathe, she thinks that is a way of me communicating with women upstairs. They cannot even hear me. Also, she will not let me be around my family or let them over. I never cheated, and when I asked her why she thinks so, she says that I communicate with women upstairs by breathing, clicking a mouse, or typing. When this happens, she punches me, bites me, squeezes my nose, throws books hard at the ceiling at walls, and breaks my belongings. Also, I have several cuts and bruises because of this. I cannot hang out with friends or go anywhere without her. She also calls me horrible names when I pay for everything and is sweet to her. I feel so depressed and saddened. She screams extremely loud when she accuses me of cheating when I am with her all the time. I do not know what is going on here. What kind of treatment does she need? Please help.