i was mad when rori slept with dean after he was married and his poor wife tried so hard he treated her like dirt.
I thought that was one of the more realistic subplots they had.
Just to keep the history straight, for those who may be newcomers to the show's canon and timeline, Dean was Rory's Very First Boyfriend.
This event did not occur until she was like 16. She had not even dated any boys before Dean, and the whole process was more like something that happens to most girls at a younger age.
The message, at least my interpretation of it, was that because of the unusually close relationship between Rory and Lorelai, which had resulted in Rory being in some ways much more sophisticated, certainly more well-read and culturally literate than most girls her age, in other ways, she had been extremely sheltered, and her socialization very limited - she had only one close friend, and spent most of her time with her mother.
So her relationship with Dean began less than a year from the time when she would begin to actively prepare to go to college, a track she had been on all her life, and it was in order to expedite that process that Lorelai made the Deal with her own estranged parents that formed the basic plot of the show - so that Rory could spend at least her last couple of pre-college years in the fancy school, thus giving her a leg up in her Ivy League aspirations.
Dean's own ambitions, his whole world view, was very different. He was just an average small town boy, as Luke would one day rather cruelly point out to him.
If Dean was the First Boy Rory ever had so much as a crush on, Jess was the First Boy she ever met with whom she actually had things in common, to whom she was attracted intellectually as well as Teen Crushally, and of course conscientious to a fault, and still unexperienced in the ways of these things, Rory fought mightily against her attraction to Jess, until she realized that having to fight so mightily was just as unfair to Dean as would be cheating on him outright, she dumped Dean for the more literary-minded Jess.
Circumstances, however, prevented her from ever "consumating" either relationship, and removed Jess from Star's Hollow, and Rory went off to college.
Dean, in the meantime, had gotten himself a Rebound Romance, who was, like him, a small town girl, with similar interests and ambitions, and although still in love with Rory, he married his Rebound Romance right out of high school, because that is what many people in small towns who intend to spend their lives right there in the town do, and like many much older and wiser people than Dean or any sitcom character
he truly believed that since he could not have the girl he really loved, he should try to make the best of it, and surely, in time, he would come to be, if not happy, then at least content.
Naturally, that did not happen. Yes, Lindsay tried very hard. But she had also made a mistake that many older and wiser people make - she had married someone who did not love her, believing that she could, in time, make him so happy that eventually he would.
Naturally, that did not happen, either, although the inevitable, in the form of Rory eventually giving it up to Dean, did happen.
By rights, this should have taken place when she was still in high school, a subtle little subtext there that Waiting is not always necessarily the best choice, because of course Rory and Dean still had nothing in common, he was not really interested in Rory's intellectual life, and Rory did not have a whole lot else to offer him that he would be interested in, since his interests were somewhat limited.
Dean was eventually obliged to acknowledge this, and he and Rory parted ways, each sadder but wiser for the experience, and viewers left to mourn the little tragedy - if only Dean and Rory had gotten their adolescent fumblings out of the way when they should have, they would have been able to part ways with their time together complete, and Dean might have been able to love Lindsay, and Rory might have been able to have a real relationship with Jess, which would have saved her from the sturm und drang that awaited her with Logan, and might even have saved her from her from at least some of her Emily nature.
As it is, we can hope that as she rode away on the train at series' end, that she rode away not only to her First Real Job, but to rediscover her First Real Love, and that Jess will not have, in the intervening time, pulled a Dean and taken up with some Rebound Romance...