Let's see. I think I've had sex with about nine women now, and at least five of them have been times when I decided the current one wasn't good enough and that I needed to move on. Here's what I've learned:
1) There's such a thing as bad sex. It's easy to recognize.
2) If you stay attracted to her, and you actually enjoy the thought of spending an hour, a day, an entire weekend with her, STOP THERE. You're in a good place.
Your gal sounds like she's playing a bit of a game with you, but she might just be trying to convince herself to finally get out, at which point she won't come back. If you want her, kowtow. Apologize profusely. Tell her you've changed your mind, that you were being dumb. Because if you stay attracted to her, and you still enjoy spending lots of time together, you're being dumb by leaving.
Believe me. I am the shark that mothers warn their little girls about. I am the one that hears the friends' threats of "if you hurt her", then hurts her anyway because he's not satisfied. . . . And I don't see myself ever, ever leaving Jin unless she bodily throws me onto the street and locks the door and calls the cops.