I’ll just add that I didn’t realize that as time went on I would be more sad about the name issue. So the fact that she agreed to give your daughter your last name but not hers, may have felt ok to her at the time, but after a few years it is getting increasingly hurtful.

You think that she should “compromise,” but really she naively gave up her “right” to fight for giving her child her own last name originally not realizing it would hurt her. So now she comes to you saying that if her daughter gets the maiden name as a middle name, this feels like the right sort of compromise she should have asked for to begin with.

If she was asking to switch our your last name for her last name entirely, then a compromise would be appropriate. But she is suggesting an actual compromise that still leans towards the patriarchy that kids get their father’s last name and she is only asking for her last name as a middle name.

I hope this helps you feel able to get over your saltiness about her not “compromising”. Sexism in our culture often has women not even realizing that something is skewed towards males to begin and just accept it as normal, and then after some time they can see that the sexism has caused some hurt and resentment and it is very difficult to deal with.