I don't know if I'm being ridiculous or not but today I got a call from mil telling me that bil and his wife are cross with me because I worded their invite to 'Mr & Mrs X X' and sil has not changed to Mrs x x. I did not know this. When they married last year she changed her name on Facebook, and they have never mentioned not changing her name before, even when I was talking about whether or not I can be arsed to change mine or not.
I don't think I should apologise, given that I didn't know and can't read minds. Is that unreasonable of me?