The family and how the new generations will do it are common worries although as you say it is nothing new because our grandparents and parents also worried about the same thing in their day.
I also believe that we have to have faith that things will work out. I used to be a bit like your husband, I liked things to go as I had planned and if it didn't happen it was the end of the world, but the world goes on, so worry about it doesn't help, does it?