After their fight, everyone went home happy. Sam made it up to Jess with the promise of a date next weekend; just the two of them. Dean can't help but think they're the cutest, grossest, cuddliest couple he's ever seen. He knows Jess makes Sam happy, but Dean can't help but wish she'd Accept Sam the way he is - weird quirks and all, not just the smart, geeky kid who wants to be a lawyer. He knows his little brother is amazing, and he wishes Jess could see all of it. He has no doubts that Jess loves Sam, but he knows that she could appreciate him more.
Friday passes uneventfully; Cas doesn't approach Dean and Dean stays away from Cas as much as possible. After school, Dean spends his time working on his Senior Project; building a car from scratch, with Bobby as his mentor. Saturday everyone gathers at Ellen's Roadhouse for a barbeque and reckless games galore. Sunday is spent out, because all parental figures are nursing a hangover and no one wants to deal with that. Bobby's extra grouchy, Crowley like poking at sore subjects, and Ellen has a shit ton of guns. Dean really doesn't want to deal with that.
So they go out and act like idiots at the local park. Not Cas' park, because Dean doesn't want to run the risk of seeing Cas there. He doesn't know how big that chance is, but he still doesn't want to risk it. That Monday, Cas tries to talk to him again. Dean's fine with it until Cas tries to bring up the past. He doesn't want to deal with that. He doesn't want to think about losing his mother again. He doesn't want to think about Cas abandoning him again. So Dean yells at Cas and storms off.
The same thing happens Tuesday. It happens on Wednesday, too. And Thursday. Even Friday. By Wednesday of the next week, Cas gets the memo. He still talks to Dean, but he avoids the past. When he talks to Dean, he takes a moment to think about the words he wants to say. Dean wants to be mean and chase Cas away, but a bigger part of him wants to let Cas back in; to tell him everything and to have Cas comfort him. But he doesn't let that happen. He's worked hard to not let that happen.
So two months go by, and Dean and Cas are somewhere between acquaintances and friends. As Dean and Cas grow closer, Sam and Jess seem to grow farther apart. Dean doesn't know if he should feel guilty; it's not his fault, it's just a sad coincidence. He knows Sam still loves Jess, but the longer they're together, the more Jess is unhappy. Dean hopes they work it out.