I Need An Explanation

A young couple gets married, and the groom asks his bride if he can have a dresser drawer of his own that she will never open. The bride agrees. After 30 years of marriage, she notices that his drawer has been left open. She peeks inside and sees 3 golf balls and $1,000.

She confronts her husband and asks for an explanation. He explains "Every time I was unfaithful to you, I put a golf ball in the drawer." She figures 3 times in 30 years isn't bad and asks "But what about the $1,000?" He replied "Whenever I got a dozen golf balls, I sold them"