I'll try my best to get to the crux of the matter without drip-feeding too much.
DP and ExW divorced over 10 years ago when their son was 1. DP was making insane money at the time and ordered to pay just under £2,000 a month to ExW for child-support (including £50,000 maintenance a year before she re-married) + mortgage free house. DP wants to be the best dad he can and whilst he no longer earns an insane salary, he still pays ridiculous monthly child-support AND private school fees. We are just about managing on the rest of our incomes but it's been a bone of contention for quite some time (but that's for another thread!).
For Christmas DPs son has asked his mum for a very expensive gift around £400 (I think a playstation or iPhone or something like that. Didn't really ask for details). DS ExW has rung DP and asked to spilt the money for the gift and shall we go over their place on Christmas morning (with her current husband and two other children) to open the present?
Um... no. This year is our year to have DPs son and I don't want to spend my Christmas morning at 'her' house (which DP paid for) waiting for son to open a present from "all of us". Surely we should buy him a separate gift from DP and I, and ExW should buy him the large gift with the money DP gives her. It's more than enough! And DPs son should not spend Christmas morning at his mum's house but rather our house as its 'our' year.
AIBU in asking her to pay for the big gift and not go over on Christmas morning?