It's my ex husband's weekend with the kids coming up and he has planned to join all his family for a weekend away at Thorpe park for his neices 13th birthday (they are going Friday and he was meeting them there on the Saturday morning). Early hours of this morning I got a call to go and look after the kids at his house (he has them on a Tuesday evening). He was in a lot of pain with his appendix and as the day has gone on he has found out it's appendicitis and he will need an op which I believe is now scheduled for tomorrow. He has already asked if I can take his place on the Thorpe park trip and I really don't want to go. 1, Even though he has said he'll cover all expenses I know I'll end up spending more and I don't have any spare cash right now. 2, I have plans to see my boyfriend this weekend and I haven't seen him for 2 weeks, it will be 3 if I don't see him this weekend. 3, even though I still get on quite well with all his family i still don't want to spend the weekend with them. My youngest 2 don't seem excited or haven't even mentioned going and my eldest never wanted to go anyway. Aibu to say no?? I feel really guilty and my ex is unsure if he'll get his money back. I said that I'm sure under the circumstances he'll be able to at least reschedule the hotel and tickets.