Disclaimer: I don't own them.
He stood there under the street light gazing in on the happy family. He saw his brother trying to fit in for his sake, trying to but failing miserably as he too just gazed off into space holding his beer, ignoring the woman and child sitting at the table with him.
Sam sighed. He underestimated Dean's love for him. He should have known that a promise wouldn't have stopped Dean from thinking about him, from wanting to get him back. No, neither of them weren't better off without the other—especially if it meant that one of them was suffering in hell at the same time.
As time passed and the dinner plates were cleared, as Lisa and Dean put Ben to bed, Sam just stood there like a statue, watching and yearning to be a part of Dean's world again.
But he couldn't. Dean needed this apple-pie life after 27 years of having to hunt evil and spending a great deal of it taking care of Sam out of necessity, yes, but mostly out of love.
How else could Sam pay him back other than letting Dean have the life that he dreamed about having for so long, but it couldn't include him, Sam.
With that thought echoing through his mind, Sam glanced back at the now-darken house, bent down to pick up the bag that lay at his feet, and turned to leave behind the brother who meant everything to him.
As he walked away down the road, one could hear floating on the wind, a whisper of "Goodbye, Jerk."