Wow, even though I'm no expert when it comes to guys, maybe he's afraid of getting into trouble with a sexual harassment suit if he ends up getting involved with you? Also, has he always been flirtatious with other women?

If so, perhaps he wasn't really interested in you romantically. Maybe he just liked the ego boost and the attention. It'd be best to just ignore him from now on. He sounds like an immature jerk. He could've at least acknowledged your email and said thanks, I'm flattered, but I'm not ready for a relationship now or something like that.

Some men just love the chase. I don't know what else to say other than just ignore him for now and keep things professional. Maybe he'll start flirting with you again if he is just after the ego boost, and the thrill of the chase. Even if he does, keep some distance. Why set yourself up for further disappointment? Move on and forget about him.