help! mil problems!

My mil is okay I guess she's not horrible but god she's so annoying!! We live with her and his brother and my boyfriend doesn't want to move out because she's all alone. Which bugs me so much! I'm pregnant, I want my privacy, I want to be able to have some really loud sex but she's here! She always has her ways to make me feel dumb. I cook and she's watching me telling me what to do. She has my boyfriend pay for everything she's 40 and works she's a teacher! And she doesn't pay for one thing! He pays for her car, insurance, rent considering the fact that he has to pay for his car as well and now with the baby coming we are trying to save money. When we buy food for ourselves she comes and starts eating out of my plate!!! Not even my boyfriends plate . MINE! Then one time we got a teriyaki bowl and fries it came with a side of ranch, this bitch ate not only our fries but my teriyaki bowl! I was grabbing fries about to dip it in ranch this bitch grabs the ranch and starts liking it! Ughhh I want to move out!!! But my boyfriend feels bad for her . What can I do?!?!?! Help!!!