For me it all rests in how it was delivered.
If partner came home and said:
I can't believe what happened tonight. So and so relative said to daughter that she didn't want you to come and put on a big sob story about how awful it would etc etc. Daughter is in a terrible state about it because it's been so important to her to have her Mum's relative at the wedding understandably but she absolutely also wants you there. But then Relative started getting aggressive/emotional/crying and said she wouldn't come and DD is now in a complete tizz
Vs
Hiya love, Aunt Midrew said she doesn't want you there, so you're going to have to find something else to do Saturday, you can't come
Dictates the scale of response!!!!
Delivery 1 you might say - what did you say? And partner might say 'i only found out after'. Or I didn't say anything because I wasn't sure what daughter wanted in the moment, it was all very awkward and I didnt want to make a scene infront of XYZ. It was in the car on the way home when daughter broke down in tears saying she didnt know what to do.
To which I might say - oh that's not fair, I don't want her upset before her wedding. Can't believe the cheek of the woman but if I have to bow out for DD then I would.
But to delivery 2 - I'd be saying oh fuck you very much then (and I'd be seriously reconsidering the relationship).
How was the message/uninviting delivered? Was it matter of fact or through tears and apologies?