Mr. and Mrs. Stewie is episode 19 of family guy season 10. It was originally aired on April 29, 2012.
Stewie meets a girl who’s just as precocious as he is, and it turns out that they have much in common including a love of advanced weaponry. Meanwhile, Lois is tired of being crushed in bed by the sleeping Peter, so she gets twin beds. This upsets Peter, who needs to cuddle to fall asleep.