Dean Forester, played by Jared Padalecki, is a main character in seasons 1 through 3, and recurring afterward. He is introduced as the new guy in town in the "Pilot". He immediately falls for the shy, sensitive intellect, Rory Gilmore (Alexis Bledel) after she shows him around Stars Hollow. Rory in turn quickly becomes infatuated with him, and he becomes the first serious boyfriend for Rory. Later, however, Jess Mariano is introduced. Although the couple was having problems before Jess, their relationship is further strained after Rory spends more time with Jess. Dean is eventually driven to jealousy by Jess' presence and this leads to the end of his relationship with Rory. He has a sister named Clara, played by Scout Taylor-Compton. It is also suggested that he may have an older sibling.
Dean later starts dating a girl named Lindsay Lister (Arielle Kebbel) and impulsively marries her. However, it is still obvious that he carries strong feelings for Rory. On the night before his wedding to Lindsay, Dean expresses to Luke- a friend who cares to his drunken state- that he feels Rory is the only girl he can marry, later forgetting the statement. His attraction to her remains so strong that, at a party, when he discovers that Jess made her cry, he violently attacks Jess, resulting in a brawl between the two (in the end, Dean threw both the first and last punches of the fight) Dean remains too close to Rory and, when it becomes clear to him that he's made a mistake in marrying Lindsay, he goes to Rory and starts an affairóRory's first sexual experience.
Lindsay eventually finds out about the affair and angrily throws Dean out, which briefly complicates things with Rory. But Dean decides to rekindle his romance with Rory (even though she now lives at Yale), much to the aggravation of many, including Luke and Rory's Grandparents, all of whom judge Dean unworthy of Rory. To make matters worse, Dean and Rory find their lives heading in completely different directions. With Rory rarely in Stars Hallow due to her life at Yale and Dean holding three jobs at once to make ends meet, the two of them rarely find time to spend together; both cancel date after date due to their commitments.
The two finally find time for a date; it would be planned that Dean would pick Rory up after a party that her grandparents planned to throw for her. However, the party was thrown with the sole purpose of introducing Rory to other prospective blue blooded boyfriends with business aspirations, including Rory's next boyfriend, Logan Huntzberger. Rory enjoys herself at the party so much that she briefly forgets about her planned outing. She eventually remembers, and by the time she walks out to a furious Dean, the two realize that their lives were heading in different directions, and Dean ends their relationship for good.
In his final appearance in "To Live And Let Diorama", Dean does not see Rory, but rather Luke. Dean relates his faulty relationship with Rory to Luke's with Lorelai, saying that ultimately, Luke would hold Lorelai back from whatever potential she may have. With this statement, Dean is never heard from again.
Taken from Wikipedia