Question: what episode do dean and rory breakup for good?
Answer: In season three's 'They Shoot Gilmores, Don't They?' Dean had good reason to break up with Rory, who'd been stringing him along for months despite clearly being more into Jess. And Dean was provoked by Jess throughout the dance, but there was no need for him to humiliate Rory in front of the entire town.