Invites to our wedding

AITA for not giving my MIL a +1 to our wedding?

My fiancé and I are getting married in December and having a small wedding (about 70 people). We rented out our favorite restaurant for the cocktail hour and reception—it’s a small, funky place we go to a couple times a month and it means a lot to us, so we want the guest list to be very intimate.

Because of the size limit, we’re not giving open +1s—only partners in established relationships are invited by name rather than open dates. We’re inviting about 80 people hoping some decline, and that already includes close friends, his family, and less than half of my own family.

His dad started dating someone during his parents’ divorce. We’ve met her a handful of times and she even stayed with us for Thanksgiving. By the time our wedding happens they will have been together for almost two years, so we invited her as a guest.

When MIL found out she wouldn’t get a +1 because of our space limitations, she got very upset and said it was rude and unfair to invite his dad’s girlfriend but not give her a +1, and that she should have someone there to make her comfortable. She also said she wouldn’t feel comfortable attending otherwise.

For context, my fiancé and his mom have had a tumultuous relationship most of his life. They’ve tried to improve things over the last several years, but it’s been rocky—especially during her two-year divorce from his dad.

At my fiancé’s sister’s wedding last year, MIL was given a whole table to invite her own friends. We simply don’t have the capacity for that. She also caused a scene at that wedding and later refused to acknowledge that people were trying to make her comfortable, which made things awkward for everyone.

We’re trying to keep our wedding small and full of people we know and love.