> what is to stop me threatening to resign every time I don’t get my way? To which I calmly explain that he didn’t have to pay (Ie. I could just quit).

This might be my English failing me but I can't understand your answer; it doesn't seem like it's actually addressing the question that was asked to you.

Could you elaborate a little further? I was met with that question before and would like to learn how to handle it well.