DH, me, our two boys, my Mum, my brother and his girlfriend are planning to spend a week in Cornwall right at the end of August/beginning of September. We found a lovely, pretty cheap, cottage, divided it by five (the boys are three and nearly one so won't take up much space!) and worked out how much we each needed to pay. We're also splitting the cost of the petrol for the three cars that are being taken and we all agreed to chip in £50 each (per adult, DH and I will add a little extra for our boys) for a 'food kitty' - not just for food shopping but to go towards a meal out/takeaway at some point during the week, and also for things like some beer and some wine for the grown ups to share! We'd all agreed on this and everyone seemed to think it was pretty fair.
But then DB's girlfriend calls me today and says she doesn't see why we all have to chip in £50 for food, etc. I explained what it was for and she said no way would she eat £50 worth of food in a week, so I said again that it wasn't just for food shopping but drinks and a meal out/takeaway as well. She said she doesn't want to do a proper food shop because that involves meal planning, which 'isn't what you want to do on holiday' but I've been to that part of Cornwall before and you either do a big shop at Tesco, which is miles away, or shop daily in the local Spar, which is twice as expensive! Plus, we have two small children who will definitely need proper meals each day so we can't really just wait and see what we feel like having.
She's put me in a bit of a bad mood about it all really. I thought we'd all agreed on an amount per adult but now she's saying she doesn't want to pay that much. AIBU to think she should really stick to what was agreed? And WWYD about it?