Confucius drew a line in the dirt with his staff and asked his student, "How can I make that line shorter"? The student suggested rubbing some of it out, but Confucius said that would be messy. "Watch", he said, and drew another, longer line next to it. "Now it's shorter".
Encourage your wife to read about other women's husbands on Mumsnet.
I can certainly certify that at least twice a month Julie observes someone else's relationship awfulness* from a safe distance, and then tells me how happy she is to have me.
*Either on a bus, or Eastenders. All of our friends and family have amazingly perfect relationships. Obviously.
Original post on Dreamwidth - there are comments there.