I have a lot of time on my hands now that I am retired, but that doesn't mean that I want to spend it wasting it.
I know that this sounds harsh.
It probably means that I am selfish. But I was put on the spot recently. I was asked to help host a bridal shower. And well, that has just never been my cup of tea, or I should say coffee. I like to be active, organized, and not be the one dancing to the whims of a couple of ladies that I can't really stand being around for more than a few hours.
The fatdroid put it down as a delima, her delima. Mine wasn't so much a delima as it was a tacklful way to say no.
I am not one for keeping thing quite for the sake of piece, if it hurts them and they retract from you, then you need to take it as a lesson learned. I would suggest being honest. Something like, "Hey X, I hate to do this but I can't help you out." You do not need to give them a reason here. If they ask. They are over stepping boundaries. They should accept that you can't make it and leave it at that.
You can also go with a more oblique, "So sorry but it just won't work, have a great time!"
Unless they are totally dense they will get it and like I said. If they pull the jerk card on you then you have learned something.
Normally when I find myself in this situation I will just write a short note on the RSVP card saying you would love to be there, but can't and you'll be celebrating them from home. Or write a short note saying you wish you could attend and you can't wait to celebrate the next time you see them.
But this depends on how close you are.
Since I was asked to help I needed to act quicker.
The woman being honored at the bridal shower really didn't make me feel like they really wanted to be there so I personally I don't feel like you need to explain myself at all, but a note card is how I will go abouthandling it.