I'll try to summerise. Friend A and friend b. Friend A lives across the road and we are close as friends and also our family's. Her son is in my dd's class and we have known them since the kids were in reception. They are 10/11 now. Friend b is also a school mum living in the village. Her DD and my DD are best friends. Me and friend b have become quite close over the past few years because of this and we also socialise with their family etc. Me, friend b and our daughters go on girls day trips sometimes. Last term the kids did WW2 at school and friend b suggested going to Amsterdam to see Anne Frank's house just the 4 of us as a girls weekend away. I love this idea. Her DH drunkenly mentioned this to friend A over Xmas cue me making excuses as too why I hadn't mentioned it to her but she says she would possibly want to come with her ds. Friend B wants to book this trip and we have both discussed it and said that we would like it to be a girls trip and that having friend A there with her son would change the dynamic of it and also make the accomodation more complicated as we all couldn't share a room. Our dd's are really excited about it being a girlie trip away.
One side of me is thinking that I can go away with whomever I choose and I don't have to include friend A but I also feel.bad about it and don't want to seem like we are leaving her out etc and damage our friendship.
If the situation was turned and she said to me that she was going away with her son and a friend that also has a son then I wouldn't expect to come with my daughter as it would disrupt the balance.
I don't think iabu just to want to go away with a friend and her daughter but I can't help feeling bad about it.