Disclaimer: I own nothing
Pairing: Jess/Rory
Setting: Sometime after Jess and Rory get together
Dean hates Jess, and everybody knows this. In fact, if Jess wound up dead, Dean would be the primary suspect. Jess stole Rory from him, and somehow made Rory believe that she loved Jess instead of Dean. Dean has no idea how Jess brainwashed Rory, but he doesn't care. Dean knew that Rory and Jess were going to break up because Rory was way too good for Jess. All Dean had to do was wait for Jess to screw up (which was inevitable) and comfort Rory and bam, him and Rory were back together and Jess was left out in the cold. Dean was not the most patient person in the world, but he knew that he wouldn't have to wait long before Rory and Dean would forgive each other and get back together. Dean hated Jess, but he loved Rory more.