I met DFriend at a toddler group and our DDs have always been close. They attended dancing together 2 times a week and regularly met up on weekends. This was usually at DFs house as my DH works from home. I would often attend as DF had become one of my closest friends. When the girls went to senior school last year I found them distancing. My DD said friends DD was leaving her out and becoming friendlier with other girls, who DD did not like. One day friends DD said something unkind to DD in front of the group of girls and made her feel small and ridiculed. After that they had a few other minor fall outs. DD is a sensitive child and would follow her friend around trying to fix it, when friend was asking to be left alone. I have since spoken to her about boundaries. They were still friends with a core group of girls but now the other girl had other friends too.
Fast forward to now. The girls are still friends but not close anymore. They no longer share lifts to dancing and do not socialise together. They do go to group events together and get along fine. It is DDs birthday next month and she is asking to not invite this girl to her party, but to invite all the other girls from the core group. I believe DD should be able to choose her own guest list but hate the idea of a child being left out. I am aware the other child may then leave DD out of her own party arrangements, and know DD would be crushed as she is very sensitive. Also I have asked her to have a smaller party so it is not so obvious that shes leaving this girl out, but she has slimmed it down to still the core girls. This would be the first party in 8 years that one child has been left out from the core group. I am aware it will ruin my friendship with the mother. I already see her a lot less as our children no longer socialise or share car rides.
AIBU to say she cant leave the child out? WWYD?