"Billy," she said, her voice slow, but firm. He was not doing this. There was a fire growing in her now that she wasn't quite sure where it was coming from, but the Doctor would likely recognize it.
"We are not doing this," she said, swatting his arm. "What kind of person do you think I am? That I'll just trade in my boyfriend for a younger model?" she asked, swatting him again several times to emphasize words.
"I don't just dump guys for a new boyfrie-- You're not Mickey, or Frod-- Okay, maybe I have a pattern, but you're the most amazing person in the universe, you don't have to be so insecure!"