"Telling Tail" joke

The woman had been away for two days visiting a sick friend in another city.
When she returned, her little boy greeted her by saying, "Mommy, guess what!
Yesterday I was playing in the closet in your bedroom and Daddy came into the
room with the lady next door and they got undressed and got into your bed and
then Daddy got on top of her..."
Sonny's mother held up her hand. "Not another word. Wait till your father
comes home and then I want you to tell him exactly what you've just told me."
The father came home. As he walked into the house, his wife said, "I'm
leaving you. I'm packing now and I'm leaving you."
"But why-" asked the startled father.
"Go ahead, Sonny. Tell Daddy just what you told me."
"Well," Sonny said, "I was playing in your bedroom closet and Daddy came
upstairs with the lady next door and they got undressed and got into bed and
Daddy got on top of her and then they did just what you did with Uncle John
when Daddy was away last summer."
-Brett