Are you overreacting or are you just reacting to evidence of observed behavior and patterns?
Your partner's ex, your partner's friend group, your partner's life choices are your partner's job to manage.
"Good news, I finally persuaded my fiancée to let me sleep with other people, now we can finally act out all my fantasies about you over Zoom!" Whoa, seems sexy!
"Inside this lady are two bigots, one is capable of acting nice sometimes and the other is not, don't feed either of them with your time, sympathy, or attention."
It's okay if someone you strongly dislike gets an inkling that the feeling is mutual.
Let's you and me drive a stake through the heart of NiceGirl™ Summer.
Content note/reminder that describing bigotry accurately sometimes includes examples. Followed by the usual reminders that boundaries are more about deciding what you will do than about what you can convince other people to do.
When fear of over-committing meets terror of letting other people down, that's where you'll find me and way more than one of you, if my inbox is any indication.
Here is blanket permission to not worry very much about offending people who neither show up to your parties nor ever explain why.
Sometimes when you stop trying to make yourself like someone, it's easier to keep the peace at parties.