Honestly, what do I do?

I don't even know where to begin, but it really seems like my fiancee does not care about me anymore.

Her mom is a trouble maker, but she defends her over me every time, no matter what. Her mom is always doing or saying whatever she can to start arguments between us. She also likes to invite her to different places, dinner, etc all the time and bans me from coming with her, and my fiancee is okay with it..

My fiancee also says very hurtful things when she is mad at me. She goes ice cold, she has called me stupid, said she is stupid for ever dating someone with two kids, says I'm going nowhere in life since I don't even have my high-school diploma (my abusive mother took me out when I was in 8th grade, she knows this and knows I'm working towards my GED). She says she doesn't feel anything for me hardly at all anymore. I have multiple health issues and she even makes fun of me about it and cuts me down for it. She doesn't want to be around me, she always stays in a different room, never wants to talk with me really.. she has been exceptionally cruel lately, and it is starting to tear me apart. I am always the reason for her problems as well according to her...

My family at this point thinks she is using me for my car and financial support, as well as a place to stay

I know the answer is probably obvious, but I want to hear it from people who aren't my family (they have never liked her).. what do I do? And not that it matters, but I want to clarify that I am also a girl.