So my family is very small and my fiance's family is enormous - like My Big Fat Greek Wedding huge. His parents had agreed to split the wedding with mine because of their majority, and there was the assumption that if it was imbalanced then it would be "proportional" to the number of guests each side invited. That was when the guest list was at 175 people, now it's at 270. Now his parents are arguing that my fiance's non-family invites should be included in my list because he's "mine" now. My father can't really afford to pay an extra 10k for an extra 100 guests. His family has done 90% of the planning since I'm in grad school and they're the majority, and it's at about $100-125/head. They can't afford it either and I don't know why they let the list get this long to begin with.
I've been snappy about about it because I get lectured about covered chairs being a luxury when those extra 10 people they added would have paid for it. I've let it for for my sake, but do I get involved or do I just let our parents work it out? I don't want my dad to be surprised by this in a few months when they ask him for a check and it's 10000 more than they discussed.