My kids are all in their 30's so this may not be relevant but here goes...
1. Not really. At the time I was reasonably fit thanks to gym, squash and karate. Now I have still have the body of a god but unfortunately it's Buddah
2. Nothing really. I had a really understanding wife regarding karate which was mainly in the evenings. The squash and gym were done before work or at lunch at the sports facility right next door to where I worked. Anne's fitness was mainly focused around walking and we both ate reasonably healthily