I am dreading my wedding because of my nMom

I am getting married next month, and my mom has been making my life miserable with the wedding planning.

She is currently giving me the silent treatment because my partner and I decided on a child-free wedding. This, for some reason, means that her sister (my aunt) cannot go unless we make an exception for her to bring her kid. We have offered to find and pay for childcare for this aunt. According to my mom, I am: selfish, unwilling to bend the rules, love starting fires within the family and need to recognize that the wedding isn’t about me/my partner.

She has tried time and time again to manipulate me into allowing an exception despite explaining to her that it wouldn’t be fair to others. I’ve given up on reasoning with her all together, but I am mourning the fact that my mom has never supported me in the wedding process once. I’m now worried she is going to make my actual wedding day absolutely miserable if she doesn’t get her way.