I can't stand my mil

Idk where to start...I live with them and my boyfriend doesn't want to move out because she'll be all alone... she 40 she can take care of herself. That's not the point, I'm pregnant. This lady eats EVERYTHING, that's what caused us to get our own fridge. I'm pregnant and bought a box of chocolates, I didn't even share with my so for a damn reason. My so came home to her in OUR room eating MY chocolate. It's just the smallest things she does bugs me!!!