A guy comes home from work and finds his wife on her hands and knees in the kitchen scrubbing the floor. She only has an apron on so the husband gets a big hard on. Seizing the moment he quickly slips it in and starts humping her doggie style. When he's through he pulls out and at the same time hits her real hard up side the head.
"What was that for?" the wife screamed "Here I am being so nice to you, letting you really enjoy yourself. Why'd you hit me?"
The husband looks at her and says "For not looking back to see who it was."