Well, do you think the guy likes you too? Does the distance bother you? Does it bother him? Can you two still see each other despite the distance? If you like each other, if you're ok with the distance, and if you two can still see each other, then I don't see why you should let the distance stop you from dating.
No, you should not beat up your ex. You can get in a lot of trouble for that. It's called assault. And no, you shouldn't just put up with his threats either. If he's threatening you then you should tell the police and get a restraining order.