It's just a zipper closing on a duffle bag, really, but the sound is so loud, Stiles swears it can be heard across the street.
On the other side of the apartment, Derek stares at him from the couch, his eyes unmoving, his mouth set in a hard line, and his whole expression is resignation – and maybe a little bit of bitter pride.
As if he's saying he knew it.
As if he's telling Stiles he knew itfrom the very first kiss that they'd end up like this.
He looks down, at their bed that it's still unmade - maybe has beenunmade for days, Stiles wouldn't know because he wasn't here – and takes in a shuddering breath.
He's not going to cry. He's not, he's not.
He picks up his bag, puts the strap on his shoulder and leaves the bedroom, stopping in front of Derek.
"You're not even going to ask me why I'm leaving?" he asks, his voice rough from the tears he doesn't want to let fall – not here, not in front of him, not this way.
"I can't make you stay if you don't want to" Derek answers with a careless shrug, his expression losing a bit of the bitterness and turning just resigned – maybe a little relieved. As if he's finally seeing the other shoe drop after so long, after so many years waiting for it.
"I don't want to go, Derek" he replies with a small, incredulous laugh.
Derek doesn't reply, just arches an eyebrow at the duffle on his shoulder, and Stiles shakes his head.
"I can't do this again" he whispers, staring at his boyfriend, who doesn't move.
He doesn't ask Stiles to stay, doesn't even ask why he's leaving, or what is it that he can't do again.
He knows. Stiles knows he knows, because he's the one who told him the very same things, so many times, but he can't anymore.
He can't do this to himself anymore. He can't.
It hurts. It hurts so damn much, because he knows where this is going. He knows Derek loves him, and hell, he loves this stupid fucking werewolf so much that some days it seems to be the one thing that matters most in his life, but Derek can't let his past go.
He refuses to be happy.
He refuses to want things, and always, always, leaves Stiles hanging. He's never there.
He disappears on Christmas, and makes excuses on birthdays. He doesn't show up for dinner with their (Stiles's, really) friends, and he doesn't return Cora's calls.
He's here, and he loves Stiles, but he doesn't love himself, and for so long, so long, Stiles thought he could heal him, help him, make him see he doesn't have to be alone. That he isn't alone, but he can't, because Derek doesn't want to – he lets Stiles in for an inch and pulls away for a mile.
Stiles looks down then, and he wants to say so much – he wants to reopen their years-old argument that Derek maybe needs help, therapy. That Stiles's dad would help them if they needed for a while, that Deaton has offered to find a therapist with whom Derek could really open up.
That maybe if he didn't want to see a professional, Stiles is here.
And maybe he wouldn't be the best choice, after all, it took him almost four years to really get a grip on himself after the Nemeton thing, but Derek was there, and he saw it – he saw it– He could do it.
He did it.
Derek could too.
But he can't.
Or better yet, he can, but he won't.
Because Derek doesn't want to be healed. He doesn't want to.
And it's awful of him to say this, but it's destroying him to be around Derek right now – they're poison.
Scott can feel their unhappiness from a mile away, and he tries to help but only ever make things worse.
Lydia keeps commenting on how much Stiles is drinking, and it's only when he realizes that the five bottles of whisky he got for Christmas are gone in less than three weeks that he starts to agree – he's falling, and he's falling hard.
Derek is taking him down, and that – that – is something Derek doesn't need.
Because Derek is a werewolf, and if he wants to drink all night, or get into a fight in a bar, he'll be fine the next morning and healed an hour later, but Stiles is breakable. Stiles is human.
He can't do this to himself.
"I wish I could have helped you" he ends up saying, his hands falling to his sides helplessly as a tear finally falls and he looks down again, wiping the tear away angrily.
"I don't need help" Derek tells him, for the first time looking angry.
And isn't that the sum of everything that is wrong with them?
Stiles nods and takes in a deep breath.
He thinks of kissing him goodbye.
Telling him not to look for Stiles ever again, or maybe just… or maybe just staying.
Instead he turns his back, getting a better grip on his bag, and walks to the door without looking back.
"I love you" he tells the man on the couch, and closes the door behind him.
Lydia is waiting for him in the car, and he gets in not even seeing anything anymore, because he can't stop the tears from coming, or the way his breath seems hard.
She doesn't say anything, just drives him home.
When they started this, years ago, he thought about their ending many times – Derek realizing Stiles was just a stupid kid with way too many issues. Or maybe one of them dying.
He never thought they would end up like this – an end, because one of them wouldn't fight for the other anymore.