The point is that the husband in the joke is supposedly so unattractive that the wife wouldn't need birth control, because she doesn't want to have sex with him.

Floyd posts some of the worst-in-a-good-way "dad jokes," puns, and groaners. He often deftly uses the board's layout to his advantage -- we read the setup and when we click through, we can see the punchline.

Sorry; couldn't help myself.