Disclaimer: Don't own, don't sue.
There are more ways of being dead
Things are clear now. You don't want her, but you don't want her to have anyone else. She's been used; she's yours in ways she doesn't yet know, in ways you're just starting to suspect. And don't you feel that kind of tickling, don't you feel your stomach churn and grumble and your heart beating faster, that's love, kind of. That's jealousy because that jerk, that nobody's trying to get to her, and she's laughing now, she's laughing and you're sure that's just another way she's fucking around with you, another way to make you suffer because you've been such a bad friend, such an asshole to her. You could've had her. You could've been together, both of you, like you were meant to be. But you had to fuck it up, you had to go and make such a mess of everything, betray her and hurt her so badly that she can't even walk straight. You see it like nobody else does. You've been there too, a long time ago, so many times that you can barely remember them separately now. Hurting and unable to say so, unable to stop smiling – shyly, you were just a kid –, unable to cry. Hiding and looking for ways to escape, and the exits are everywhere, really, everywhere, but you can't find them. She can't find them, either, so she's got him.
They're going to kiss. They're going to kiss and then fuck and then marry, they'll have three children and a dog and will live happily ever after and she won't even remember you, you know. Why would she. What have you given her, after all. She will be happy and she will be free, maybe, and she won't have to pretend not to have seen you when she walks through the corridors, and it will be okay. And you, what will become of you, poor and small, a survivor who's barely making it through life right now, right when it's easy. You will be lost; you will be nothing without her, no one. But you'll hang on. You've always done that. You're good at it, even now. And you will miss her, but you'll forget – you've forgotten your own mother, don't think of her even when you come back home to her, to him, to the pain and the fear and the hiding in the closet because you're still so small, so frail.
Life will go on. And she'll have him. You'll be alone.