Hermione Granger/Severus Snape
The first time she saw him out after, he is with a tall and perfectly made up witch with long Auburn hair and piercing green eyes and it hits Hermione like a bullet to the chest. The impact steals the breathe from her lungs. Her throat tightens to the point of pain as her eyes begin to prick with tears against her will.
That was supposed to be her. She is the one that is supposed to walk in on his arm with her head held high knowing that he is hers. Hers. No longer hers though. No, not any more. The memories are too painful to give into. Like an open wound that refuses to heal; becoming inflamed with each encroaching thought.
When she had him it was like her entire being was wrapped in sunshine. He had this way of making her feel seen. Like his entire focus was on her. If only she hadn't said those three little words. Three words is all it took to make her world fall apart and shatter. She is still bitter that it's all it took.
She now knows that some loves just aren't meant to last. Even when you connect on a soul level. Even when you know they are it. Even when your heartbeats sync with another. If time and fate aren't on your side, there's nothing you can do to counter it. It took a long time to accept this fact, but accept it she did. When she looks at him the pain is still there. Now though, it's a bit dulled and doesn't feel as if her insides are on fire. She can actually look at him without flinching, and for this she is proud. Maybe one day she will be able to look upon him and it won't even hurt. She isn't holding out hope for it but the possibility is enough.