The problem as you grow older is, how do you let somebody close who’s basically a total stranger?” he said. “Nature came up with a trick: It’s called attraction. Sexual attraction brings down all the barriers, lets you get close to a new person in a physical way that you don’t get close to your family.”Over time, of course, this physical connection wanes. While many bemoan this loss of titillation, Dr. Levine celebrates it. “It’s smart,” he said.
https://www.nytimes.com/2017/10/12/style/should-your-spouse-be-your-best-friend.html
How my heart sings 