Summary: The problem is—the problem is during that year, Derek falls in love.
And so does Stiles.
But not with Derek.
Author's Notes: This piece was inspired by DevilDoll's AMAZING ficlet, which can be found on tumblr. I highly recommend reading that one first. Summary quote is from DevilDoll's ficlet, which you can find here: devildoll dot tumblr dot com [slash] post [slash] 39623102048 [slash] i-am-adding-this-ficlet-to-this-post-the-original
She's perfect for him, so Stiles falls hard and fast.
Amanda's from the next town over; they met at some sort of regional science fair or something. She loves video games and Batman, laughs at all of Stiles' stupid jokes and smiles at him when he's not looking. She's nearly as smart as him, but much more focused, and she always encourages his research and tangents. Her family loves him, the Sheriff loves her, and she's the best kind of stabilizing influence.
Derek wants to hate her, but he can't. She is sweet and pretty and kind and she loves Stiles. How could he hate anyone who loves Stiles?
So instead he pulls away. Not all the way away, but far enough that he can nurse his wounded heart in private. It's made easier that Stiles fills the time he used to spend with Derek with Amanda. That's not to say he abandons the pack, because he doesn't, but he also has his own life now.
They go to the same college, Berkeley, and fall even more in love. They start making plans: whether and where to go to grad school, where to live, what to do. Whether Amanda should be told about werewolves.
("Not yet," Derek says when Stiles asks.
"Why not?! It's been five years, and she'll be cool with it! C'mon, man."
"I'm sure she will be, Stiles, but not every couple makes it past college." At Stiles' outraged noise, Derek adds, "I'm not saying you two won't, but I don't want to tell her now to have you guys break up in two months! The more people who know..."
Stiles gets it immediately, Derek knew he would, because his expression softens and he says, "Yeah, I get it."
"Thank you. Give it a year or two, and ask me again."
Some couples don't make it that far. Derek knows they will.)
In the meantime, Derek meets Karen. She's a beta from a neighboring pack several hours away. She's nice and funny and she seems to like Derek. They get along well.
Her alpha approaches Derek about a match. She goes on at length about how good Karen and Derek are together, what that kind of match would mean for the two packs, how good and strong an alliance between them would be. Derek nods in all the right places and says he'll consider it, that he'll talk to Karen.
He does, and she agrees, so they start courting each other. She's no Stiles, but Derek likes her, could see himself making a life with her.
Their courtship is almost over, negotiations all but complete, when Karen confesses.
("I'm sorry, Derek, but I can't lie to you about this. It's not fair."
Karen's practically wringing her hands, but Derek's bracing for the worst. She's smelled a little off, a little sad, for a while now, but he hadn't been able to figure out why.
"I like you, I do, you're a great guy, but I'm not in love with you." She breathes for a moment, "I'll understand if you want to call this off, but I couldn't go through with the match and not tell you."
"Oh."
"I'm-it's not-Steve. I'm in love with Steve," she sighs.
Derek's only met Steve a few times, but he's been Karen's best friend since they were children. Steve, however, is happily married with a baby on the way.
"I'm in love with Stiles," Derek replies. Karen's never met Stiles, but she knows who he is.
"Oh. So...," she trails off awkwardly.
"Yeah."
"We're still on, then?"
"You're not Stiles and I'm not Steve," Derek starts, "But I like you, and I think we could be good together. Even outside the match and the alliance, I think we could work. It's not what we want, but," he shrugs.
"But it would be good. Yeah." Karen tears up a little, laughs self-deprecatingly. "Yeah, okay.")
It works out; the match goes through, and they get married. Karen moves into the Hale House, which had been renovated years earlier, and they settle in. They have a baby, then two, then four. Erica and Boyd get married and move into a wing of the house. Stiles and Derek tell Amanda about werewolves; she takes it just as well as they thought she would. Scott marries a beta from Karen's pack, and Allison moves away. Stiles and Amanda get married and move to Virginia, starting a family of their own.
Things get easier, especially with Stiles across the country. They still talk, and sometimes Stiles visits, but with now with his own life Derek can think about Stiles less, if not love him less.
Fifteen years after Derek and Karen marry and Stiles is still in Virginia; Scott, his wife, Erica, and Boyd still live in the Hale House; Isaac's settled down with a lovelyhuman man in the center of Beacon Hills; and Karen comes home smelling of tears and Steve.
("He wants to try," she says. Steve's wife had died several years ago, so he'd moved back to be closer to his family. He and Karen had become good friends again.
Derek would be lying if he said he wasn't jealous, but he's not lying when he says, "It's okay."
"We only held each other, I wouldn't do that to you."
"I know," he says and wraps his arms around her. She smells of Steve, but she doesn't smell of sex. "I wish you love and happiness," he says.
"Thank you."
"You can't stay in the house, but I see no reason to dissolve the alliance. I'd appreciate it if you waited until after the divorce, though."
"Of course," Karen kisses him. "The kids'll stay here, more space to run. Steve's been talking of moving to Beacon Hills for a while, so if that's okay?"
He nods. "You're welcome here anytime.")
The divorce goes smoothly and Karen moves into town. Steve joins her soon after. The kids are confused, and a little upset, but their parents still get along and they're allowed to move freely between the houses as long as they tell everyone where they're going. Steve's very nervous at first, but once Derek sits him down and explains that he knew the whole time, it gets better.
Everyone's most surprised at how angry Derek isn't. Stiles, in particular, can't seem to grasp it. He calls, more than once, to rail against Karen on Derek's behalf. It takes a lot of convincing from everyone (except Karen and Steve) to get Stiles to back off.
Derek is hurt, but it's only because Karen gets a chance at something he never will. He could never begrudge her the chance, though. And Derek's content, not as happy as he could be maybe, but happy enough. He's still got a chalkboard somewhere in the attic with 61 chalk lines on it, but it's okay. It was never meant to be, and Derek accepted that a long time ago. He was never going to get to be deliriously happy, but he's not miserable, he's not even unhappy. He'll take it.
He opens his eyes to find himself on the ground. Stiles has trapped the faerie inside a circle of iron, and has an iron knife poised above its chest. He's pleading with Derek to "Wake up, wake up, please wake up."
Derek grunts, says, "M'okay."
"Jesus, thank god," Stiles breathes.
The faerie shrieks at Derek, "No! No! Kill me and I ensure it happens! Kill me and it comes true!"
Derek stares up at Stiles, who's waiting for Derek's go-ahead, and thinks about the chalkboard in his bedroom with 357 chalk lines on it. He thinks about Stiles and Karen and Amanda and Steve and kids. He thinks about 61 lines and how he'll never stop loving Stiles.
"Do it."
