A portion of the dialog is from the Purgatory scenes in 8x02.
Dean was in love with Castiel.
He suddenly knew that with complete certainty. He had never really allowed himself to think about his friendship with the angel, to try and analyze what exactly it was between them. Even while he ran through Purgatory these last few months, first alone, later with Benny by his side, all the time searching for Cas, he was careful to never look too deep into his reasons and motivations for doing that. He'd just always kept going, hunting monsters, getting information out of them, ganking everything that came in his way.
For months there had been only one thought in Dean's head. 'Find Cas and get him out of here.' And now he had found him.
When Dean had finally been able to look through the trees and see the clearing by the stream, he had suddenly stopped, unable to move, and just stared at the man kneeling by the water. Even from afar he looked so different, but still unmistakably Cas.
The moment Dean's eyes fell on the angel, the 'Find Cas'-thought was replaced with a new one. 'I love him'
All his actions of the past suddenly made perfect sense to him. Of course he had become depressed and drank even more than usual after the Leviathans walked Cas' body into that reservoir. Of course Dean had been shocked and devastated when Cas had finally woken up in that hospital and remembered him, but had gone crazy and didn't want to work with the Winchesters anymore. And of course Dean had spent nearly a year in Purgatory, despite knowing a way out, just to find the angel.
He was hopelessly in love with the guy. A part of Dean knew that this wasn't the astonishing new realization it felt like in this moment. That part had known this all along, but crippling fear had prevented him to even consider exploring this line of thought.
But now, when he finally saw Castiel again after months of searching and missing and being scared that Cas maybe wasn't even alive anymore, all he felt was love and relieve. There was no fear, no concern, no doubt and realizing that made him downright giddy.
Then Dean suddenly woke out of his daze and nothing could hold him back anymore. "Cas!" He yelled.
When the angel stood up and looked at him, Dean all but ran the rest of the way separating him from Castiel. He couldn't help laughing in relieve and hugged him tight, savoring the feeling of Cas in his arms. Then he reluctantly pulled back, but not before clapping Castiel's shoulder again.
"Damn, it's good to see you. Nice peach fuzz." He said, lightly stroking Castiel's bearded cheek. Dean knew, he normally would never do that, but now every excuse to touch Cas again, was welcome.
"Thank you" Cas said, uncertainly glancing at Benny.
Dean couldn't help but feel that the angel didn't seem to be very happy to see him – both of them actually. He tried to shake this feeling. Of course Cas was glad to see him, why wouldn't he be?
"You should meet somebody. This is Benny. Benny, this is Cas." Best to get the introductions over with.
"Hola." Benny said, not very enthusiastic.
Castiel however didn't acknowledge the vampire, instead turning to Dean again. "How did you find me?"
Dean still couldn't stop the tiny smile that came from just seeing Cas alive and healthy. "The bloody way." He answered. "You feeling okay?"
"You mean am I still..." Cas pointed to his head, making circling motions with his finger.
"Yeah, if you want to be on the nose about it, sure." Dean said smiling.
"No. I'm perfectly sane." While Cas talked, he was looking around the whole time, obviously checking for enemies. "But, then, 94% of psychotics think they're perfectly sane, so I guess we'd have to ask ourselves, 'what is sane?'"
"That's a good question." Dean answered.
He was starting to get a little worried. But before he had a chance to think about Castiel's behavior, Benny interrupted their conversation.
"Why'd you bail on Dean?" he asked Cas with a hostile look.
"Dude –" Dean tried to interfere, but Benny just went on.
"The way I hear it, you two hit monster land, and hot wings here took off. I figure he owes you some back-story."
Benny didn't seem willing to let it go, so Dean felt obligated to defend the angel.
"Look, we were surrounded, okay? Some freak jumped Cas. Obviously, he kicked its ass, right?" he turned to Cas, looking for confirmation.
"No." Castiel seemed unable to look Dean in the eyes at this confession.
This simple small word was like a stab to Dean's heart.
"What?" he asked incredulously.
"I ran away." Castiel answered, again averting his eyes.
"You ran away?" Dean just couldn't believe what he was hearing.
Cas didn't seem happy to admit this, but apparently didn't regret his actions.
"I had to."
"That's your excuse for leaving me with those gorilla-wolves?" This was too much; Dean felt his heart breaking more and more with every second of this conversation. There he was, freshly enlightened and ready to confess his feelings and Cas… how could he do this to him?
"Dean –", Castiel tried to say, but Dean wasn't willing to hear his defense.
"You bailed out and, what, went camping? I prayed to you, Cas, every night."
"I know." Cas said, looking to the ground.
"You know and you didn't..." Dean broke off, taking a breath. He tried to stay calm. "What the hell's wrong with you?"
"I am an angel in a land of abominations. There have been things hunting me from the moment we arrived." Castiel was regaining his determination, looking Dean in the eyes once more.
"Join the club!" Dean shouted, getting seriously pissed now.
But Cas didn't seem willing to back down.
"These are not just monsters, Dean. They're Leviathan. I have a price on my head, and I've been trying to stay one step ahead of them, to –", he broke off, eyes darting away as if he was searching for the right words. Then he returned them to Dean's eyes and confessed, "To keep them away from you."
Dean's eyes went wide, he hadn't expected that. There seemed to be a whole world of truths behind those few words. Before he could find a reply however, Cas went on.
"That's why I ran."
Dean could feel Benny's gaze upon him. Obviously the vampire too, had sensed that there was more to this conversation than the words would suggest.
Castiel didn't seem to have noticed the shift in Dean's mood.
"Just leave me, please." He said dejected.
"Sounds like a plan. Let's roll." Benny was quick to answer, but Dean interrupted him at once.
"Hold on, hold on." Dean was convinced, that Cas had only run to protect him. He had been alone, running and hiding in Purgatory for nearly a year, just to keep Dean save. And if the pain in his eyes was any indication, it had been horrible for him. Once again Castiel had risked his own safety and even his life for Dean.
A new flicker of hope sparked in Dean. Maybe there was a chance for them to sort out their relationship once they got out of Purgatory, a chance for Dean to finally tell Castiel the truth about his feelings. Cas deserved to know that he was loved, even if Dean didn't dare to hope, that there was more than friendship behind the angel's actions. Dean wouldn't leave without him.
"Cas, we're getting out of here. We're going home."
"Dean, I can't." Cas didn't even look up. He seemed to be resigned to his fate, to never leave this awful place.
But Dean wasn't having that.
"You can. Benny, tell him."
"Purgatory has an escape hatch, but I got no idea if it's angel-friendly." Benny told him reluctantly.
"We'll figure it out." Dean was quick to add.
"Cas, buddy, I need you." He needed Castiel to understand that he wouldn't leave without him.
"Dean…" Cas sighed. He looked so troubled and pained, but at the same time there was so much fondness in his eyes and voice.
Dean sensed that this was his chance. If he didn't screw up now, he could get Cas to come with him. In the blink of an eye, he made up his mind.
"You know what? Screw this!" he said, looking at Cas. "When I was up on that hill and saw you down here, I realized something. And now I'm done pretending, I'm done lying to myself or others, I'm done ignoring something so important."
Cas was looking very confused now and Dean knew Benny had taken a few steps away from them. A vampire with decency, who would've thought something like that existed.
Dean made sure to look firmly at Castiel before going on.
"Cas, I don't need you. I… I love you! And I know I don't deserve you, but I need you to know, that I can't leave you here. Loosing you again… This time it'd kill me for sure."
"Dean." The name sounded like a caress coming from Castiel. "Dean, do you really mean that?"
Cas' eyes were wide open, shocked and something else – hopeful maybe?
"Cas, of course I mean it. I met Benny months ago." He vaguely gestured in the direction of where the vampire was pretending not to listen. "I've known about the way out all this time. But still we spent every waking moment running through monster land, looking for you. I could never have left without you. I've…"
Whatever Dean had wanted to say next vanished from his mind, when Castiel made a strangled noise and next thing he knew, Dean had an armful of warm, smiling angel.
"Dean… I…" Castiel stammered, his face impossibly close to Dean's, his hands on Dean's shoulders and his eyes… those eyes, suddenly so full of joy. Then the angel's lips were on his and Dean didn't even need a second to get on with the program and kiss back, fiercely.
Dean had had a lot of first kisses in his life, but this was a whole 'nother level. He sounded pathetic and sappy even in his own head, but this right here, kissing Castiel, feeling his angel's tongue softly caressing his lower lip, begging for entrance – which of course Dean was quick to give – this was pure heaven, despite where they were.
Just when Dean thought it couldn't possibly get any more perfect, he had to breathe and Castiel seized the opportunity and whispered "I love you Dean."
And that was the moment Dean Winchester learned what true happiness felt like.
The End