Fed up with my MOTHER IN LAW! HELP!

Ugh!!! Being pregnant and dealing with a husband whose mom has become a nightmare is exactly that! I feel like I'm living a nightmare! My mother in law became widowed 4 years ago. And since then has become more like my husbands wife then myself! She lives abroad but that means nothing! She calls daily asking for money! The have secret conversations. When I ask he says its private, when I confront him about the abnormality of his relationship he says I'm the sick one. I am very close to both my parents but doesn't not mean I hide my conversations from him or walk out of the room or talk in the car when I'm not around! I don't know what to do! We helped her for 3 years and that wasn't enough she tells him that it's his responsibility to take care of a 44 year old woman I'm so tired I cry all the time, I've become so bitter. That was never me. It's getting to the point where I feel like telling him to pack up and go live with her cause most of the time his priority is her!