What to do when your mother in law hates you...I mean really hates you!?

My boyfriend and I have been together for 5 years, we are getting married in June. My soon to be mother in law hates me....I don't know what to do. I've tried to have a conversation with her, she gives me a bare minimal answer, the only time she ever calls us is to have my boyfriend watch his little brother (almost every weekend) She kicked out my boyfriend and chose a drunk loser over him because he wanted my boyfriend out, she moved this guy into her house only 2 months if that after curtis father ped away, didn't even introduce him to us, he just showed up one day and never left. Curtis has been living with me for the last 3 years, my parents took him in after she kicked him out. She has called me a wh**e and has shoved me around (curt and i had been together for about a year and cheated on me and i was trying to leave their house and she wouldn't get out of my way and told me that I was such a ***** and that I deserved what he did to me). My parents do everything for my boyfriend and I, I mean they go out of their way to help us. They buy us dinner every weekend, they spend time with us, they even call my boyfriend but, he never answers their phone calls. They buy curtis anything he wants, anytime he needs new shoes they buy them for him. They give us money, they let us live in their second home rent free now after they bought bigger home and moved out of state. His mom never call us to ask us over for dinner or even to hang out, it is always you NEED to hang out with your brother. I mean I feel that the only thing curtis is to her a babysitter so she and loser a$$ boyfriend go out and get drunk or whatever else. I'm completely at my wits end with this! I have no idea what to do, we both dislike each other. I've tried to tell my boyfriend that she hates me and he throws these huge fits saying that I don't want him to have anything with his family and thats not it at all. I just want to be accepted, but I feel like this will never happen. I mean when we go visit them, she won't talk to me at all, unless curt is in the room then she "acts" like she likes me, but once he leaves she gives me horrible looks. She has NEVER called me just to ask how my day is (I mean in 5 years!!) or how the wedding is going or even offered to help us with the wedding, which is fine because my parents are. But, she told us she wouldnt let us get married on the beach actually her words were "over my dead body", but she is NOT willing to pay for a thing!! She wants me to getting in a warehouse at her work!! UGH!! I have no idea what to do and I feel like this is going to ruin what my boyfriend and I have together. Can someone please help me?