We don't live together but had planned to do something together with the DCs (he has 4 and I have 2) on New Year's Day. But now he has said he has plans to go and play board games with his friends for afternoon/evening on New Year's day, and do I fancy looking after his younger two DCs 
If not, he says he'll ask his DD1 (14) to do it. Feeling rather peed off as I'd though we were going to do something together. I like his DCs and they're good company for mine, (and we could feasibly do something all together on a different day) but looking after all of them with no other adults for company wasn't what I'd planned to do on New Year's Day :( Told him I'd have to see what other plans I could make with my own friends first and see if his DCs wanted to fit in. Or should I just have said no?
Am rather hoping that his DD1 has plans of her own and says no too.