Mother-in-law Hell

My future MIL believes herself to be the Goddess of the Earth and that every one within her realm should fall at her feet and do everything that she demands. I don’t think so! I  know that she is a two face, manipulating, B#@$%. I am actually putting my wedding plans on hold because I can’t stand her and I am having serious doubts about marrying my fiance because of her. She doesn’t like me because she can’t control me and I won’t let her rule my life. She tried to dictate to me my wedding plans and said I was spending to much. All of our wedding and reception expenses would have been about $2,500. I pointed out that this was cheap compared to what other people paid for their wedding and that since she wasn’t paying for it, it really wasn’t any of her business. I said this after about the 20th argument over the wedding plans.

Now she is undermining me to my future step daughter who lived with us for about three weeks. Future MIL basically said I had to right to an opinion about anything to do with her grand daughter even though she was living under my roof. I wasn’t punishing her, but I was helping to set up the house rules. Future MIL told her she didn’t have the listen to me. Luckily before anything major happened future step daughter moved back in with her mom.

I don’t have any children of my own and my fiance and I have decided that after we have been married about a year, if everything is okay between us we will start trying to have a baby. She has told my fiance and several other people that she prays that he is sterile or I am barren. I’ve told my fiance that she will never have anything to do with any child we have. And if some one in my family acted like she does or came up with a list of reasons why we should break up, I wouldn’t talk to them. Of course we argue about it but what do I do? What kind of person wishes that on another human being. Any words of wisdom?