I honestly don't know from where this came. Anyway, thanks to Marinka for beta-reading it so long ago :)
Severus hated watching her with him—hated seeing her laugh at something he said or seeing her lean her head on his shoulder. It made his heart clench painfully, knowing that he had never been enough for her.
It made it even worse when he saw the same cycle in the boy he considered the closest he would ever come to having a son.
Although the boy never knew it, Severus had observed Draco staring at Potter and the Weasley girl many times over the years. What he saw reflected within those grey eyes made Severus' stomach clench in recognition.
He had felt that same resentment and jealousy before in his own life and knew that the boy, however much he might deny it, was envious of Potter—not only because of his fame, but also because he had captured the heart of the beautiful Ginny Weasley.
Just as Severus lost his Lily to James Potter, Draco lost his own red-haired beauty to James' son.
As Draco waved goodbye to his son at the train station, he couldn't help but see the way Scorpius glanced at Lily Potter when he thought no one was looking. The sight sent him back to his own school days spent tormenting Harry Potter and his friends.
It hurt to think of the lively young woman who had so often been at Potter's side, but he bore the burden gladly. If he could not have her in reality, he could at least dream about her and the life they would never share.
Astoria put her hand on Draco's arm and drew him away from the platform. She knew better than to ask him what was wrong.
Many times, late at night, her husband would lock himself in the study and not come out for hours. He would do nothing but look into his pensive, reliving his school days alongside Harry Potter.
Draco might have scored tiny victories now and then, but as the old saying goes, "he won the battle but lost the war." The war, in this case, was over a girl—a smart, beautiful, amazing, strong girl he never could have had.
Even though Draco didn't look at her the way she had seen other husbands look at their wives, Astoria still loved him with all her heart.
Theirs had been an arranged marriage and love was not expected. Nevertheless, it had happened, slowly at first, but steadily growing within her as time went on. It pained her to see him gaze out the window, a faraway look in his eyes as he thought about the happy couple on the front of the Daily Prophet.
Yes, she was envious of the woman who had so effortlessly captured his heart, but she didn't blame her husband. He cared for her and their son more than she could have ever hoped.
Scorpius enjoyed watching people. He could always tell what they were thinking or feeling just by the way their mouth twisted or their eyes dimmed; no secret was safe from him. However, the one person he really wanted to figure out was a mystery to him.
She pranced around the school, her shinning mane of red hair flying behind her and dozens of friends flocking like the sheep they were. A smile was always on her face, except for when she became angry with one of her brothers or many cousins. There was in her a goodness and purity that called out to him, but he knew he could never answer. Their lives were just too different.
That didn't stop him from watching.
Later in his life, Scorpius learned of Severus and his father's respective secrets. He couldn't help but chuckle softly when he saw the similarities to his own.
On his deathbed, he turned towards his young grandson and told him but one thing before he breathed his last:
"Stay away from the red-haired ones, boy. They'll bring nothing but heartache and stomach ulcers."