Once they’re back home, Dean and Cas start spending a lot more time together. See, Dean has been praying to Cas (and dreaming about him) nearly every night, for almost two years. Now that he finally has him back, he’s not letting Cas out of his sight. During his time in Purgatory, Dean finally faced the fact that he was in love, and whether Cas felt the same or not, it was a big goddamn deal to Dean. When he came back from Purgatory without his Angel, Dean swore to himself that, if he ever got him back, he was done pretending, done with the macho posturing and ‘no-homo’ bullshit that had kept Cas at arm’s length for so long. Cas meant the world to Dean, and he deserved to know it.
So, now that they’re all living together in the bunker again, they still hunt, they still research, and fight, and almost die, and everything they’ve always done. But they’re a little more domestic, too. Dean cooks almost every night, when they’re home. He keeps the bunker surprisingly clean, and washes all the cars in garage once a month. Sam goes for runs every morning, and though he’s still a little sad over the end of his relationship with Amelia, he starts ‘talking’ to a girl he meets a couple of towns over. The boys have movie night every week, when they can, and Dean and Cas always sit together on the couch, sharing popcorn. By the end of the first movie, they always end up sitting much closer than they started out, and Dean never straightens up or moves away. A couple of times, he’s fallen asleep before the last movie ends, his head resting on Cas’s shoulder, a small, shy smile on Cas’s face. Sam has definitely not taken a surreptitious picture of this with his phone. It is absolutely not the cutest thing Sam has ever seen. Nope.
Unfortunately, Dean still has nightmares, and sometimes they’re so bad that he wakes up screaming. The only thing that seems to keep them at bay is Castiel’s presence. So, after a month or so, Cas starts spending the night in Dean’s room. (For the first week of this, there is a lot of smirking on Sam’s part, and a lot of eye-rolling on Dean’s part.)
At first, Cas sits in a chair next to Dean’s bed, reading. Then, one night, Dean has a particularly bad dream that he won’t wake up from. Cas climbs into the bed and wraps his arms around Dean, trying to calm him. When Dean finally wakes from the nightmare, he won’t let go of Cas, so he stays put, holding Dean while he falls back to sleep. After that, he stays in Dean’s bed every night.
Soon enough, Dean’s nightmares fade, and his dreams become much more . . . enjoyable. He wakes up wrapped around Castiel, hard as a rock, morning after morning. He’s a little embarrassed, but Cas never bats an eye about it, so Dean refuses to make it weird or awkward. Eventually, though, Cas has had enough of hearing Dean moan his name, writhing in his sleep, and then just going on about his day. When Dean wakes up this time, Cas leans in and kisses him. And that’s all it takes.
From then on, there’s outright affection, handholding, kissing, and sex. Lots of sex. They don’t talk about it and don’t define it, but they don’t hide it from Sam, either. Or from anyone, really. If they get a funny look from someone when they’re holding hands, or when Dean wraps his arm around Cas’s waist in public, Dean simply stares the person down. It’s usually a guy. Women seem to think it’s the sweetest thing they’ve ever seen.
After a couple of months, Dean suddenly starts wearing his old silver ring again, but this time it’s on the ring finger of his left hand. The next day he gives Cas a key to the Impala. They don’t discuss it.
One day, almost a year after Cas came home to the bunker for good, the boys are at a diner on the last day of a case. They’re making small talk with the woman who owns the diner with her husband. The lady grins at Cas and Dean, and asks if they’re married. Cas gives a little shake of his head and says, “No, we’re not”. At that, Dean’s eyebrows climb into his hairline, and he turns his whole body to face Cas.
“Excuse me?” Dean says.
Cas just tilts his head and furrows his brows, looking perplexed. “What?”
“What do you mean, what?!” Dean says, in a dangerous monotone, his eyes widening. The diner lady exchanges a pointed look with Sam, and quickly moves away, attending to other customers. Sam shifts in his seat, looking at anything and anyone except his brother and best friend.
Cas still looks confused. Dean, now red in the face and nearly apoplectic, just gapes at him for a few seconds. “What the fuck is your last name, Cas?” he growls.
“Winchester.” Cas replies, without a moment’s hesitation.
Dean blinks at him, pausing in his outrage, but dammit, he’s got a point to make here! He holds up his left hand, wiggling it in Cas’s face. “I’ve been wearing this for months, Cas. You didn’t notice??”
Cas glances at Dean’s ring, and nods. “Yes, of course I did.”
“I haven’t worn a ring in years . . . YEARS! . . . and then it suddenly makes an appearance, on my left hand. When, exactly, did I start wearing it again, Cas? Huh?”
Cas looks down, thinking back to the first time he noticed that Dean had started wearing the ring again. It was the day after Dean had finally said that he loved Castiel; that he wanted Cas with him “forever”. Ohhhhh!
Dean sees the lightbulb go off in Cas’s head, and smirks, expectantly. “What the hell did you think I meant, Cas?”
Cas stares, open mouthed, at the love of his long, long, life. “You really mean ‘forever’?” he whispers.
Dean reaches for Castiel’s hand, a soft smile on his face. “Of course I do, Angel. You’re it for me.”
Cas stares down at their joined hands, running one fingertip across the metal band on Dean’s finger. “Can I have a ring, too?” he asks, shyly.
Dean grins, leaning forward to press their foreheads together. “You want one?” Cas just hums in agreement. “Then I have just the thing.”
When they get back to the bunker the next day, Dean heads directly to the weapons room, then to another storeroom. When he returns to the library, he’s holding a scroll and one of their spare angel blades. They use the spell on the scroll, along with some of Cas’s grace, to melt down the angel blade, and craft it into two beautiful rings. The inside of each ring is inscribed: “for my Hunter” and “for my Angel”, along with the Enochian symbol for Union. That night, they exchange vows and rings, with Sam as their witness. Sam cries.
For the next several weeks, Cas takes every possible opportunity to tell people that he and Dean are married. He tells, waitresses, bartenders, grocery store clerks, victims on cases, Kevin, Charlie, Meg, and Crowley.
Kevin is completely unfazed, since Sam had texted him The Big News as soon as the ceremony was over. He comes back to the bunker after a weekend LARPing with Charlie, casually high-fives the happy couple, and heads to the library.
When they see Charlie a few days later, Castiel barely says hello before he blurts out, “Dean and I got married”. Charlie squeals in excitement, wraps Cas up in a bear hug, then punches Dean in the arm. “Oww! What the hell, Red??” he splutters, rubbing his arm. For a tiny little thing, Charlie has a pretty good swing. Charlie arches an eyebrow at him and says, “THAT is for not inviting me to the wedding, jackass. What am I, chopped liver??”
When Cas tells Meg, she smirks, but her eyes look a little sad. She tells Cas, “Awww, it’s about time you made an honest man of him”. Then she claps Dean on the shoulder a little too hard. “This is a dark day for bar skanks everywhere, but I’m happy for you. You take good care of my unicorn.”
Crowley looks genuinely happy for them, oddly enough. His only comment is a gruff “Took you damn fools long enough”, but when they get back to their hotel room an hour later, there’s a bottle of champagne, a waffle maker, and a bouquet of white roses, with a note saying “Congratulations, Squirrel & Feathers”.