I make my wife drive as much as possible with the camper in tow, gives her practice on how to tow it.
She never liked to tow before but ive been on her to learn how to do it just incase of an emergency, my teenage son knows how to hook up the trailer so if im ever out of action they can both tow and hook up, shes even getting better at reversing.
Myself personally cannot sit for long periods so my wife has to take over for trips longer then 2 hours, she understands and is very happy to take control.
You could always pull and injury and make your husband do some driving, or find a way to make it fun for him again.
My grandfather drove everywhere, even 6 weeks after a triple bypass and right up till he passed away.
My uncle on the other had makes my aunty drive everywhere and has basically given up on life and everything to go with it so i know what your saying.