DPs mum has an eating disorder. She doesn't really eat much at all, and rarely drinks more than water. Generally I find it quite awkward when we eat out, she's lovely and I'd never pressure her to eat, but restaurants tend to spend the whole time offering her something to eat or drink.
She decided a month or two ago that she didn't want to cook at Christmas. We invited them to ours, but they didn't answer. They called DP on Wednesday, on his way home from work, and they said they were booking a chain restaurant. I wasn't there, but DP said he didn't really want to go there and arranged to meet them before or after. All fine.
On Friday we met them, and they wanted to eat our with us. They were a bit annoyed that the chain restaurant had sold out, and we called round about sixteen different places, but very few places had space for four people. Eventually we found a nice place nearby, me and DP have eaten there a few times and it's lovely. They gave no opinion despite being prompted many times, so DP paid and it was sorted.
Yesterday DP met his mum while I was at work, and she confided that she didn't want to go there as, forty years ago and before DP was born, they had a "break" and DPs dad slept with someone from that town. They have no idea if she still lives there, or anything, but she doesn't feel comfortable there.
I went there today and enquired about reducing the number to two, or getting a refund, but the booking is non refundable.
AIBU to think they should have told us before we paid? I could try and get two other people to join us but we won't be able to eat with them then - it wasn't "their year" but they'd be quite upset, I think, hence us going to eat out with them instead of cooking for ourselves like we wanted to. It's not been cheap 