Turn over!

Santa and Banta are having beer one night when Banta announces that he's going to divorce his wife, Preeto.
"Good grief" says Santa, "You and Preeto are the happiest couple I know - why on earth would you want to divorce such a lovely woman after all these years of obvious bliss?"
"Well" replies Banta, "Truth be known I'm just bored with poking the same hole night after night after night. I guess I'm hankering for a bit of variety."
Santa, "Well if you want variety, why don't you just, you know, turn her over every now and again?"
Banta, "What - and have a house full of kids???"