John=strong, dignified man who needs to be *sold* on why he should waste any more time on a juvenile, cheating, misbehavin' fool.
Stay in character.
I'd love for YOU to decide when the night is over, rather than letting her linger as long or as little as she likes. I wonder if you should set up an "out"... someone you can text at the end of the night, who will then call you, pretending to need your help for something. "Oh, gotta go help a friend with something."