I've namechanged as other posts are too outing.
The backstory: My brother is getting married in a week, midweek, and it's out of town so everyone is having to stay in rented accommodation from the Tuesday. It's not his first 'location' wedding, albeit only a few hours drive from where we stay. My primary school age kids are part of the wedding party so we have to be there. I'm also 38 weeks pregnant and not convinced the baby is going to stay put for long.
Well it turns out the day after the wedding when we're due to go home and need to get our pets from the cattery/kennels by aleatory afternoon, the couple are hosting a second party/celebration in the evening. We're already spending a fortune on this wedding and I'm terrified I'm going to go into labour in the middle of nowhere and now we're expected to stay an extra night (albeit my mum has offered to pay our accommodation). The kids are also having to take two days off school for this but we can't really negotiate a third day as they're still doing course work and school weren't particularly happy about the two days off (we won't get fined but possibly referred to truancy officer for unauthorised absence). We'd have to pay (if there's a space) for the pets to stay another night at their boardings.
Anyway to the problem: my mum has fallen out with us for saying we're not attending the second night's celebration because the kids have to go to school on the Friday and well I'm about to have a baby and am extremely uncomfortable. Apparently I'm being unreasonable and selfish because she's bought the kids outfits to wear for the second party.
I think I know the answer but just want to check, Aibu for not staying another day for the party?
Also wtf is with three day long celebrations of weddings? Why the fuck are people doing this?