You knew I was going to chime in here, Fred!
Sexual issues at 40+?!!? 40 + what? 25, 30 maybe? Why on earth would you think you think sexual issues start so young? My husband is 60, Fred, and last time we had the house to ourselves, he was going for #3 till we got interrupted. If you're both on the same page, things will never get stale.
You are right about looks not mattering as much as you grow old together. Being overweight will always matter, though.
And I love your last sentence about building a family together. Again, I am reminding myself that you're still in your 20s.