My (30f) fiance (28m) doesn’t want me using a specific word?

I don’t use this word a lot but we were waiting in the drive thru for our food for 40 mins and I more lightheartedly said that I had to “piss” (I had already said a few times how I needed to pee, restaurant was closed and locked and we were stuck between cars) and he told me not to use that word and that it’s “unladylike”

I was somewhat taken aback, showed him the gossip girl “go piss girl” meme and he’s still insisting that it’s unladylike to ever say?

Am I weird for feeling weird about this? He dared me to post it here and see what y’all say 😭 We’re relatively progressive although I grew up in a conservative family and it’s reminding me of that sort of tone-policing personally….

TL;DR: Fiance doesn’t want me saying “piss” because it’s “unladylike”