My mom's mom divorced my grandfather before I was born and he married a wonderful woman who I call grandma. For my entire life, and probably before I was born, my mom's mom has been a miserable, nasty woman. She sends back any card or gift my mom sends to her and sends my mother mean letters that detail how she failed as a daughter and as a parent (neither of which are true. My mom is one of the most generous, loving people I know.) She's rebuffed every attempt I made growing up to be a good granddaughter, and once I found out how she'd been treating my mom all those years I stopped trying.
She lived out of town but recently moved back and was invited by my uncle to one or two family cookouts, both of which were extremely awkward. She has no reason to treat our family this way. My grandparents, aunts and uncles are amazing people who respect others.
If you stayed with me this long, here is my problem:
I don't want this woman at my wedding, and neither does my fiance. She constantly makes snide remarks to me and to my mom, and the last thing either of us needs on that day is to worry about how she may act. The problem is, my mom wants to be a good daughter and can't seem to accept that I don't want her there. She says it's not right to leave her off the guest list because it's her mother.
Is there any way I can convice my mom what a bad idea it could be to invite her? I know that I would be able to put aside my feelings and be polite, but I worry that she will make trouble for my mom, and that's the last thing I want my mom to have to worry about on a day that's supposed to be happy.
Help!