Slapstick:

They accounted for my unflagging courtesy and optimism, and perhaps for my failure to age as quickly as other men. I was seventy years old, but I had the vigor of a man half that age.
I had even picked up a pretty new wife, Sophie Rothschild Swain, who was only twenty-three.

Slaughterhouse-five:

Rumfoord's left leg was in traction. He had broken it while skiing. He was seventy years old, but had the body and spirit of a man half that age. He had been honeymooning with his fifth wife when he broke his leg. Her name was Lily. Lily was twenty-three.