Reporter asks elderly couple for the secret to their happy marriage, but the answer is a surprise

A couple was celebrating their golden wedding anniversary. 

Their domestic tranquillity had long been the talk of the town. People would say, "What a peaceful and loving couple."

On this special occasion, a local newspaper reporter paid them a visit. He inquired as to the secret of their long and happy marriage. 

"Well," explained the husband, "it all goes back to our honeymoon. 

"We visited the Grand Canyon and took a trip down to the bottom of the canyon by pack mule. 

"We hadn't gone too much farther when my wife Ruth's mule stumbled and she almost fell off. Ruth quietly said, 'That's once.' 

"We proceeded a little farther when the mule stumbled again. Once more my wife quietly spoke: 'That's twice.'

"We hadn't gone a half-mile when the mule stumbled a third time. Ruth promptly removed a revolver from her purse, hopped down off the beast, and shot the mule dead.

"I SHOUTED at her, 'What's wrong with you, woman?! Why did you shoot the poor animal like that? Are you crazy?'

"Ruth looked at me and quietly said, 'That's once.' "