Back story
I WFH i am the main cook and I do the shopping.
DH self employed works very very long hours - sometimes depending on how big the job won't get home until 10pm.
There is no set arrangement when DSS will come to us, as he's old enough now to make his own arrangements he will just ring up last minute "Im on my way home" and that's the only notice we get. Sometimes if I'm lucky I'll get 24 hours notice. We can't refuse him because his mum sometimes doesn't come home at night, (don't ask - whole other thread needed for that!) so DH isn't happy with him being in the house on his own overnight as he gets scared very easily.
Because of this casual arrangement I have no idea how many people i'm cooking for, DSS has a large appetite so not like I can just give him a bit of mine and a bit of DH's - he would need a big portion. It isn't always things that can be frozen either and I'm reluctant to keep making extra portions on the off chance DSS will want to eat.
He also has allergies (not life threatening, just makes him itchy) so when he does come here if i haven't cooked something he isn't allergic to I then have to cook a whole different meal for him
Sometimes hes already had food when he comes here and isn't hungry, other times hes had food and still wants more when he gets to us, other times he hasn't had anything and I won't know until the last minute - we have our evening meal around 8pm on the nights that DH gets home at a reasonable hour so if DSS eats at 5pm after school he will want another meal at 8pm or depending how big the meal was he might not want much just something small.
DSS cannot cook for himself and in any case our kitchen is really really tiny so 2 people in the kitchen cooking at the same time would not work so it's always left up to me to sort. If he is at his mums he just orders takeway.
Three nights ago he had told us the day before he was coming to us and would be having food with us - great - i can then plan.
So i cooked enough for all three of us, ensured it wasn't anything DSS was allergic to, then he rocked up as i was plating up and casually said oh yeah i'm not hungry I had KFC with my mates half an hour ago...
DH doesn't think its a big deal and just says its fine, ill just eat his portion but its really not the point IMO! I think it's really disrespectful towards me as I'm the one worrying about what to buy, what to cook, having something quick in the freezer that i can just throw in the oven if he turns up.
DH doesn't worry because he doesn't have to plan, cook, go shopping and thinks i'm massively over reacting about something so petty.
AIBU to insist either he eats with us or he eats at his mums and to let me know which one within plenty of time??
He's a very sensitive soul so bringing this up usually leads to floods of tears that its not his fault he was hungry so he already ate etc - of course i'm not saying he shouldn't eat if he's hungry but to at least let me know??