This couple has made a vow never to be more than fifteen feet away from each other. When one is in the restroom, the other stands outside the door. When boarding a plane and they cannot be seated next to each other, they do not take the flight. They eat the same foods from the same plate and often read the same book, waiting until one or the other finishes the page before continuing.
And, they're celibate.
See:
Buddist monks will never separate