From the ArcaMax Publishing, Jokes Newsletter:
http://www.arcamax.com/news/jokes/s-568872-755794
A suspicious husband hired a private eye to check on the movements of
his wife. In addition to a written report, the husband wanted a video
of his wife's activities.
A week later, the detective returned with a film. They sat down
together and proceeded to watch it.
Although the quality was less than professional, the man saw his wife
meeting another man! He saw the two of them strolling arm in arm and
laughing in the park. He saw them enjoying themselves at an outdoor
cafe. He saw them dancing in a dimly lit nightclub. He saw them take
part in a dozen activities with utter glee.
"I just can't believe this," said the distraught husband.
"What's not to believe?" the detective said. "It's right up there on
the screen!"
"I simply can't believe my wife could be so much fun!" the husband
replied.