ok confess I only scanned the responses ... BUT

Why are you mad at him ? He didnt do this
Why does it take the whole weekend? He didnt invite her and he shouldnt have to entertain her
Why does it ruin tonight? why cant you still go out
so, you dont want to do the "family" thing ... ok - but thats DINNER .. on Thursday -- not the whole day, not friday, not saturday

SO after dinner - he picks is Arse up -- sys dinner was great (you do the same) and then you 2 do your thing (no details here please image

Honestly - I dont see the big issue

I would be upset - yest
but if casual - why mad

if maybe more than casual - yest upset -- BUT there are work arounds .. if its WORTH working for
if not
then dont be mad = do your thing, he does his - and y'all pick up where ya left off = whenever you can (or want to)