Dr. Oz says Dr. Hendrix's theory has medical backing. When you are first in love, he says your body releases natural chemicals like dopamine, which is related to addiction, and oxytocin. "That makes you feel love and warm and cuddly," Dr. Oz says.
The romantic phase—with its natural high from chemicals—begins to wear away after a few years, Dr. Oz says. "Which sort of makes sense because that way the child is old enough that if the pair splits, they can make it," he says. "That's why I think you have to reinvent the marriage every five to seven years. You've got to reconnect."