Dump her

"You know what?" you shout at her, "Fine! I don't need a girlfriend who just shows herself off. We're through!"

Kristen just scoffs. "Good luck with finding another girl like me!"

With that, you hear her go into your bedroom and hear the window open. You rush outside to see her, still naked, throwing your stuff out the window as you frantically catch it and she tears you a new one about how loyal she's been and how badly you're messing up.

This goes on for hours until you finally get "packed" out and crash the night on a friend's couch.

You don't think much of this until six months go by, when you bump into Kristen again.