handling women who starts weeping in reaction to her own behavior

For some reason I often come across bipolar women who blow up, and when they find me not reacting, start to find an excuse to start crying and showing how much pain they are in. There was one time when I caved in out of sympathy and she used it as an excuse to confront me again. The alternative, to be a heartless bastard, didn't appeal to me much at that time (pre-TRP days). What are some correct ways to handle a woman who is crying on demand?