Its been difficult between them lately. They never used to be like other couples. Chatty or tactile but this feeling of distance hurts. It used to be so easy. A perfect fit but now Stiles is too tired to talk and Derek is being even more repressed and closed off than when they first met. Things have been bad for them. Stiles knows this but it still hurts when he sees Derek eying her from across the room with a single-minded focus that stiles rarely sees anymore.
The thought of Derek leaving him, of them not being able to fix this, tears his heart open in this throbbing mess of pain. He wants to fix it. Fix them, but he doesn't know how. The way Derek still clutches him at night makes him think Derek wants to fix it too. He ignores it. Hopes it will fix itself. But things aren’t that simple. He buys Derek gifts that feel empty. Conversation is stilted if any.
Derek starts staying out a lot. Says he has things to take care of and tells Stiles not to worry about it. He comes home looking wrecked and smelling like perfume. Stiles tries not to notice. Tells himself its Ericas. He sees them in a coffee shop smiling and looking like all the worlds most gorgeous couple. It’s her, from across the room. He imagines them in the Hale house kids running around and smiling like they are now. He wonders if throwing himself off a cliff and landing on the rocks is as painful as the glass shredding his chest. He realizes he’s depressed.
Something like quiet acceptance whispers that maybe it’s better this way. That they just weren't meant to be. That sometimes people fall out of love with each other, and that's okay. He decides he needs to break up with Derek so they can both move on. In the coffee shop she waves and gives him a friendly peck on the cheek while Derek watches after her with a small private smile. Yeah, stiles thinks, it’s for the best. He has a date set and starts setting things up to move out.
Derek doesn't come home for a few days. He comes home with lipstick smudges. When Stiles tells him, Derek's hand goes to his mouth and his eyes widen almost imperceptibly before he goes an angry shade of red and stomps out the house.
He comes home to find her draped all over him; his arms around her shoulders. Her clothes scatter the floor. Her lips kiss bruised and hair disheveled. She’s asleep from what stiles imagines must have been a brutal romping session judging from the bruises covering her body. Stiles closes his eyes tight when Derek says stiles “It isn't what it looks like” and forces himself not to give-way to the hysterical teary-eyed laughter. Forces the words :It’s okay Derek. I understand.” and watches as the tension bleeds out of Derek’s shoulders.
He gets the duffel bag he prepared and leaves. The sticky notes one the door tells Derek that “He honestly hopes there happy together and that he’s sorry it came to this.” He hears Derek call his name but Derek doesn't chase after him like some part of him was still desperately hoping…maybe this will be just a bump in the past one day. He goes over to Scott's and balls his eyes out on what he says is the last time for the death of what he once believed was true love. Just for today. For today he'll cry good heavy tears before trying to pull himself back together. He allows himself only one day to mourn or he'll never stop.