AITA for not letting my neighbor take my children swimming?

I have 3 children between ages 3-8. Today my husband was supposed to take them to the park but he procrastinated and now it’s too late because he has to leave out to an event. Our sweet next door neighbor ended up messaging us to see if the kids could join her child at the pool (our children enjoy playing together).

My husband thinks this is a great idea since they were excited to go to the park but are no longer going. He told the children about this exiting new option to go swimming instead before bringing it to me. But I said no. I am 40 weeks pregnant, exhausted and it’s much too hot for ME to go and sit at the pool w/ my children right now (which is why dad was supposed to do the park w/ them).

I am sure my neighbor would not mind me sending them out by themselves because again she is so kind and sweet and I don’t think for one second that they will be unsafe with her. Sending THREE children w/ this lady to the pool all by herself on top of her own child is selfish in my opinion. I would also be the parent dealing with the aftermath of swimming like hair and baths etc.

My husband thinks it’s not fair to the kids because they now have to “be stuck in the house all day with nothing to do”. They have plenty of toys, board games and a whole backyard to play in, as well as each other. They will be fine and again, had he moved faster then they would have been able to stick to the original plan and been back from the park by now. In his opinion there is no difference in sending them to the pool without me since I wasn’t going to be joining them at the park. Now the children are upset and I look like the bad guy because I won’t let them go to the pool