A/N: This is just a really short one-shot I made a while ago to test out my rusty writing skills. Originally posted on my ao3 account.
Dean wasn't stupid.
He could see how Sam and Castiel looked at one another; small, fleeting glances that he would almost miss. He could see how they touched one another; gently brushing their knuckles against the other's, or those secret touches he was sure they didn't think he'd notice. He could see many things about the small gestures they made, the ones others would dismiss as friendly. But Dean knew, he knew deep down in his heart that they were not just touches, glances, and gestures close friends made. He knew they were something more.
And the thought alone hurt more than he could imagine.
Dean was conflicted with himself. On one hand, his baby brother found someone he could be himself around; no pretending, no lies, no secrets. Cas knew Sam was a hunter, he knew about the consequences that came with the job, and yet, there is is.
But, on the other hand, he just didn't like it.
It was as if his moose of a brother was only attracted to the supernatural. Jessica was Sam's first steady relationship- normal relationship. Everything after her wasn't. Hell, even before Jessica he was with a freakin' Kitsune.
That wasn't the only thing that bothered him, hurt him. What hurts him the most is he knows Sam won't tell him about the relationship he and Cas share. He knows his brother, his baby brother that he swore to protect since the age of four, will keep it a secret from him. He can see the guilt in Sam's eyes -whether it's from the withheld secret or the regret of his past mistakes- and it makes his heart clench to know his brother won't tell him.
It was times like these where he questioned his brother's trust. Sam couldn't even trust his own brother with his relationship status.
Did he think he would disapprove? Did he think he would desert him? Did he think he would be disgusted because he was with a man? One who used to be an angel of the Lord?
The fact that his brother might have these questions swirling through his mind hurt.
And then, there were other times where he just stood by and watched. He watched as Sam seemed to glow, his normally old and tired eyes sparking with adoration and -dare he say it- love. Sam, his once beaten and broken Sam, smiling and laughing like he used to.
Not only was Sam happy, but Cas as well. Cas' awkward, tiny smiles began to grow more confident and genuine. His stiff moments of affection slowly smoothed out and he was able to hug without questioning the purpose of the action, or downright rejecting the idea of displaying his human emotions without the fear of 'using them wrong'.
He would sometimes just watch both men break out of their shells to make eachother laugh, smile, and just plain happy.
These moments were the moments where he could forgive Sam for not indulging him on his relationship with Castiel.
The boy with the demon blood screwing around with a former angel of the Lord, Dean thought with a wry smile while he watched Cas laugh at something Sam said; Sam grinning ear-to-ear, obviously proud with himself.
Wouldn't have it any other way.