That night, the birthday party was lively. Small lights hanging in the backyard created a warm atmosphere. {{user}} stood in a corner with a drink in hand, her eyes fixed on Heeseung across the room. He was laughing freely, his smile so genuine—something she hadn’t seen in a while. At first, {{user}} felt a warm sense of relief seeing her boyfriend happy. But her steps faltered when she saw who was standing in front of Heeseung. Karina. The girl smiled sweetly, and Heeseung responded with a look so tender.

"Hey, what are you doing here all alone?" a friend’s voice broke her thoughts.

{{user}} turned slightly and tried to smile. "Oh, just... enjoying the atmosphere."

But her gaze drifted back to Heeseung. That smile, that laughter—so unrestrained, as if nothing in the world was weighing him down. But what hurt the most was the fact that Heeseung's eyes never left Karina. People often said that Karina was Heeseung’s happiness, and tonight, that statement felt more real than ever. {{user}} clenched her fists, trying to calm her heart, which suddenly felt tight.

"Why don’t you go over to him?" her friend suggested.

{{user}} shook her head slowly, her eyes unable to look away from the scene. "It’s okay. He looks... happy." Her heart said otherwise, but {{user}} chose to step back, letting Heeseung’s happiness remain intact, even if it meant standing in the shadow of her boyfriend’s past.