I think your guys number one problem is expectations. If you want to go then go. Just don't have any expectations that it will change anything. If you don't want to go then let them know why you don't want to go. Say something like "W we are not a family anymore. I need time to heal and move on and spending time with your family will delay/prevent this process right now. Make it clear that this is how you feel right now.
You guys also have to remember that your Ws are likely 2-3 years ahead of you in this process. They have mourned the end of the marriage but may not want to completely cut you out of their lives. You may also feel the same 2-3 years down the road. That is why they are ok being friends.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712
