FSIL (BIL fiance) is hard work and quite immature. We went away for a family do and we're all staying together in an Airbnb. She did nothing but goad me. Her attitude included "shotgunning" the biggest room. DH physically can't fit in a double bed because he is too tall. Normally this isn't an issue because he just hangs his feet off the end. Ultimately the alternative double had a foot board so I slept on bunk beds in a different room so he could lie diagonally. It wasn't ideal but it wasn't a huge problem, just would have been nice for FSIL to be thoughtful enough so DH and I could share a room. Over the course of the day there were lots of these irritating but not life altering behaviours. Others noticed she was nitpicking at me, complaining at my walking speed and criticising that I paid full price for a top. So when she was literally arguing for arguings sake I called her out. She quietly stormed off and called me a cow under her breath. I lost my temper, not at anyone, but told DH what I really thought when some of his extended family were around.
AIBU to have called her out? I wouldn't put up with her shit if this was any other environment in my life (like work).
I know I shouldn't have lost my temper because I embarrassed DH. And as he says "if you fight with pigs you'll get dirty and and pig will enjoy it".