DGPs are divorced. DC1 has a performance on an upcoming evening. I have asked DF to look after DC2 so that DH and I can both go to watch the performance. DM would like to go to the performance too. Initially this was a moot point, as there were no tickets available, but now one has become available. However I feel it might be unfair for DM to get to go while DF has to do childcare. WWYD?