Before going for a few days to her mother's, the jealous wife took her ten-year old son aside, gave him chocolate and told him, "Keep an eye on your father and the maid and let me know what they do."
On her return, she asked her son if there was anything to report. The son nodded.
She dragged the boy before her husband and said, " You cheat. I got you this time. Son, now tell us what you saw dad do with the maid."
"The same as you do with the milkman when dad is away," replied the innocent son.