She's not my wife

Johnny's wife arrives home from town and says to him, "Remember those headaches I've been having all these years? Well, they're gone. No more headaches."

"What happened ?" asked Johnny.

His wife replies, "Margie referred me to a hypnotist. He told me to stand in front of a mirror, stare at myself and repeat, 'I do not have a headache', 'I do not have a headache', 'I do not have a headache'. It worked ! The headaches are all gone."

"Well, that IS wonderful," Johnny says.

His wife then says, "You know, you haven't been exactly a ball of fire in the bedroom yourself these last few years. Why don't you go see the hypnotist and see if he can do anything for that ?"

Johnny agrees to try it.

Following his appointment, Johnny comes home, rips off his clothes, picks up his wife and carries her into the bedroom. He puts her on the bed and says, "Don't move I'll be right back."
Johnny then goes into the bathroom and comes back a few minutes later, jumps into bed and makes passionate love to his wife like never before.

His wife says, "Johnny, that was wonderful !"

Johnny says, "Don't move - I'll be right back."

He goes back into the bathroom, comes back and round two was even better than the first time.
His wife sits up and her head is spinning.

Johnny again says, "Don't move - I'll be right back."

With that, he goes back in the bathroom. This time, his wife quietly follows him and there, in the bathroom, she sees Johnny standing at the mirror and saying, "She's not my wife", " She's not my wife", "She's not my wife !"