Well you've now answered your own questions OP, your MIL is pissed off at you because you've failed to tow the line. I wonder whether she's ever heard the old adage 'A daughter's a daughter all of her life, a son is a son until he gets him a wife'? This is actually very true in the vast majority of cases, as your own daughter is far more likely to allow her Mum to be present at the birth of her children, whereas a DIL who has never been seen naked by her MIL, is very unlikely to want her to see her when she's in a state of undress, and totally vulnerable whilst giving birth. As for the son only being a son until he gets him a wife, again, in most people's opinion, once a man marries, his wife and family SHOULD come first, and take the place of his Mother in his life.
My advice regarding your going NC with her stands, although I do think you have to give your DH the choice. You're a strong woman, and she doesn't like the fact that together you and your DH have decided to make your own family traditions, which don't include her, therefore you will NEVER win with her, and so would be wasting your time making ANY effort toward her.
I actually had a MIL like this, who hated me from the time we got engaged. Things got really bad after having our first child, as MIL was constantly pushing our boundaries, so we ended up going NC for several years. Due to a family bereavement, we started seeing them again, but even then she hadn't learnt her lesson, and so we ended up going NC again. There was then a family wedding which brought us back together, but on this occasion I told the in-laws that things that had happened between us were not going to be brushed under the carpet this time. I laid down the law about what we would and wouldn't accept, and my DH backed me up. From that point onward things changed, and by the time MIL died, we were actually on very good terms.