We've obviously had different life experiences. Yes, most of the publicized criminal stalking cases you hear about on the news are about men but most of pure stalkerish behavior I've personally encountered in my life has been perpetrated by females. I would say at the very least 75%+.
When a guy gets his heart broken by a girl he generally licks his wounds and moves on when he is able. Girls don't tend to let go so easily. When they believe they've found "their guy" something really dark clicks inside them and they will go to great lengths to keep their teeth locked into his flesh if he tries to pull away.