Rock the truth is if you go or don’t go it doesn’t change anything. If you have a special needs child then you and your W being friendly moving forward will certainly be beneficial.
My voice these days on the board is more about getting to a point where a spouse having affairs doesn’t work for the poster. Where the poster is able to drop the fear of the future and actually embrace the unknown and look forward to it.
I suspect your W has an agenda and wants to show the kids you can be friendly and be in a social setting together while all singing kumbaya.