They want to.
Want to hear a clean joke? Bob took a bath. With Bubbles. Want to hear a dirty joke? (Punchline hidden so you don't accidentally read)
They want to look like their mothers.
ME: I made a cloning machine. WIFE: Don't do anything stupid. OTHER ME: Like what
The husband.
Because if he goes on air, he'll die.
Some Stormtrooper
Husband: "Because I don't want to wake you."
Because her husband had a hollow weenie