Talking stage but more emotional..guy admits to having a fwb and won't stop it. You:

Act like nothing bothers you, bc it truly doesn't. He isn't yours yet.

Talk to him about it because it hurts you. He listens, but still doesn't put an end to it. You stay.

Everything in 2nd answer, above, except that you leave..because fuck that, you are the prize.

Wonder why I have made this oddly specific poll.