M: The Blacks got divorced.

W: Really? Why?

M: Mr. Black has been getting a little on the side.

W: Really? I am surprised. He doesn't look like a guy who'd ever cheat on his wife, does he?

M: No, he doesn't. Anyway, his wife found out that he has been two-timing for a long time.

W: Well, I am really surprised. By the way, have you done anything behind my back?

W: No. The only thing I've ever done behind your back is zipping you up.

M: I like that joke, but I hope it's true.