First I would wait for her to bring this up!!! This is a vacation!!! As for S16 being forced to stay when he doesn't want to!!! No! He will throw a fit. If she plays the "well I guess I will follow yada yada yad crap" let her. You need her away from EFG and away from anything else that reminds her of the affair.
You want to go home....your son wants to go home....so go. She will hem and haw about having no choice etc. You need to get away from that place and also get her away. Once your there I would give it until summer, then she needs to be fully on board or out. But don't have that conversation while you here!!! Get her on your playing field. You going to know alot about where you two are here in the next few months. If shes just going thru the motions you will know soon.