I read a quote today that said what we resist persists, it's only when we look at something it can end (or something like that)
I think you have to look at the positives. Instead of seeing it as being left out, think about how great it is that they're spending time together and that after a big day you can have a day to yourself to rest, relax, and recooperate.
It was a big turning point for me where I decided to actually be HAPPY for H that he was going to a concert of an artist I love that I wasn't going to.
SS, in your thread you were so excited about the upcoming air show, spending time on the boat with H alone, and you always talk about how things around his kids are strained..so look at the positives you get all to yourself in a few days and you don't have to deal with the family drama!
don't choose to look at things as a rejection. no one can MAKE us feel like a victim.