Wrote this as a one-shot for a contest at Hogwarts Is Home: Insomniacs on Livejournal, I have decided to share it with you all since it's my only Harry Potter fic that is finished. I hope you enjoy it!
*Anything Harry Potter related belongs to J. K. Rowling, the interpretation is all my own.
As Severus roamed the cold dungeon corridor on the way to his office, he couldn't help but think back when he would stride down this hall in the evening hours to steal away in the empty Potions classroom. For hours he would bury his mind in his work of correcting and perfecting every potion recipe he came across. It was here that he decided to bury his feelings for Lily Evans all those years ago. Had Potter and his lot kept their arrogant noses out of Severus' business, he and Lily would never have grown apart. She would still be alive.
Slamming the office door behind him Severus slouched onto the couch tucked into the corner, half hidden by shelves full of odds and ends. He closed his eyes and sighed, letting his thoughts drift for the millionth time to what his life would have been like had he not been sought out by the Gryffindor gits.
Graduation day was a glorious day. This was the day he would profess his love for Lily and ask her to spend the rest of her life with him. Severus was a bit nervous, though he knew he had nothing to worry about. He and Lily had grown up together, been dating for three years already, never a harsh moment between them. Sure he had been worried in their fifth year when Potter was sending Lily love notes and small gifts, but she always told him to shove off, though much nicer of course. As the ceremony dragged on, Severus fidgeted with the small box in his pocket, going over his small speech to Lily in his head.
Three years later Severus is holding his daughter and feeding her while Lily gets a few hours' rest. Their beautiful daughter is almost half a year old, has her father's hair color and her mother's eyes. Severus smiles as she yawns and closes her eyes. In eleven years' time she will receive her Hogwarts letter and he will proudly accompany her to school as Potions Master. Dumbledore had granted him the position after two years of apprenticeship with a highly skilled master that works for the Ministry. Lily will continue to work at the Muggle library in town, books were always a passion of hers and she insisted on not taking advantage of Dumbledore's kindness and ask for a position at the school, though he does allow her to visit for a few days at a time. He can see himself and Lily growing old in their little house on the outskirts of town, watching grandchildren grow and leave for Hogwarts.
A single tear streaks down Severus's face as he breaks from his reverie. He moves to the adjacent room containing his sleeping quarters, only removing his shoes before collapsing onto the bed. A slow steady stream of tears stains the pillow as Severus croaks out a whispered, "always."