Mother in law from hell

My mother in law thinks its ok, to be mean and nasty towards me! I just sit and listen where she is coming from. All she asks about is about me losing weight (she thinks I'm fat), money(not too much of a problem), and now she's wanting for me to prove that I'm a US Citizen because she doesn't want her son dating a nonwhite person( I'm Mediterranean and middle Eastern).

I don't take this crap from my own parents, why is doing this. We moved in to help her because she's disabled. But I'm sick of her treating me like trash. Its sucks because I'm too nice to tell her to stop. I need help.

Yes my boyfo knows and he's doing his best to handle her when he's home. She only does it when he is gone.