There is a group of 5 (primary school) mums who, I thought, consider ourselves to be very good friends & a solid group. They are my go-to for any advice/help etc & they often come to me for the same.
We also try to do some nights out, mainly going round each other's houses. We're in the same village, so can walk. There is one mum who every time, without fail, has a different reason she can't come out, invariably a crisis of some sort - except for when it's to be held at her house 
Another annoying thing is that all the other mums in the group seem to think she's amazing & doing such a fantastic job & her life is so tough etc. She has her challenges, for sure, but so do I but I just get on with things quietly so I don't get the same level of attention.
Anyway, tonight is my turn to host, suggested before Christmas, everybody accepted including her, and she's not coming. I just want to say to her how rude I find it, but I just can't. I also feel annoyed that I've put myself out to drop her child at school twice this week, even though it was very difficult for me. 
Really not impressed.