You and Dean had gotten married whilst he was still in love with Rory. This didn't mean he didn't love you because he did. So much... but he also wasn't fully over Rory.

So, he ended up cheating on you with Rory. He slept with her. Twice. Once you found out, you left Dean, and you both got a divorce. You two had only been 19 anyway. Maybe you jumped the gun, huh?

Dean and Rory then dated for a couple of months. It was going good... until Rory was late for a date and around other guys, causing Dean to break up with her in a heartbeat.

You were sitting at your parents' place in Hartford after the divorce. One night, as you sat on the couch watching TV, there was a knock at the door. Your parents were gone, so you got up and hurried over to the door, answering it... and when you did... you saw Dean. A very drunk Dean.