AN: This is not a happy fill. Not at all. Actually it hurt to write it so... yeah. But a couple people wanted to know what happened with Sebastian and what made him think Kurt was cheating. Short answer is that Seb was a jerk and lost his marbles a little bit. Longer answer below. Send me prompts so I can write something happier now?

Sebastian sat at the dinning room table and tapped his fingernails against the wooden surface. Kurt was chatting away about his day and eating the dinner he'd made for him and Sebastian. Candles lit the room and cast light in Kurt's sparkling eyes. He was happy. Smiling and enjoying their anniversary dinner.

Sebastian wasn't happy, but either Kurt hadn't noticed or was choosing to ignore it. Probably the latter, which would explain his inane batter, trying to cheer Sebastian up? Or trying to gloss over the reason Sebastian was upset. Kurt was smart he had to know that Sebastian knew. And now he had made this dinner and tried to fill the silence between them with happy chatter.

It wouldn't work. Kurt wouldn't get out of it that easy. The longer Sebastian sat there the more angry he got.

Kurt was a cheater. A liar and a cheater. They were still newlyweds in the world's eyes, in their "honeymoon phase" and Kurt had fucking cheated on him. And now he sat there like nothing had happened. Like it wasn't a big deal. Like Sebastian was stupid and didn't know or wouldn't care.

Sebastian had started having suspicions about Kurt's faithfulness a couple months before. Kurt spend less and less time at home, he always took extra care, even for him, with his appearance before he went out, he was so damn happy, and Kurt had always been so easy to lead along and to boss around now he was getting a mind of his own. He was seeing someone else, Sebastian knew it.

There was a chance that Kurt just loved San Francisco, Sebastian thought, maybe he just loved decorating their home, and was happy and feeling independent. Maybe Kurt was just trying really hard to make California work when where he really wanted to be was New York. Maybe... but no, that wasn't it.

Sebastian hadn't been completely faithful himself. He had never been someone who could just commit to one person. In truth he'd been cheating on Kurt and having one night stands ever since they'd started dating, and marriage hadn't changed him. Sebastian knew from the beginning it was only a matter of time before Kurt cheated too.

Sebastian's hands curled around his fork as anger red, hot and unreasonable boiled in his blood.

It was late, very late. Sebastian had gotten home from "work" late. Really he'd been with his lover, some guy who'd mentioned that Sebastian husband was a catch and he'd do him any day, Sebastian may have decked the guy before storming home wondering who Kurt was fucking. Kurt had been at home cooking. Apparently they'd missed their dinner reservations so Kurt made them something.

Kurt stopped talking about... whatever it was he'd been going on about and looked up at Sebastian with a sigh.

"Seb, it's our anniversary." Kurt said. "I know you're upset about... something, but couldn't you try to enjoy yourself?"

Sebastian lifted his eyebrows. "Upset about something?"

"Do you... want to talk about whatever it is?"

Sebastian let out a bark of cruel laughter, "No. I don't think so."

Kurt lips and jaw tightened the way they did when he was upset or angry. Sebastian could tell he was biting back what he really wanted to say.

"Okay..." Kurt sighed. "Then I guess I'm going to head upstairs. We can do the dishes tomorrow. Give me a few minutes and then come and join me?"

Sebastian nodded and then watched Kurt go upstairs. He waited a few minutes like Kurt had asked, but as he did his anger just grew.

Kurt was going to pretend nothing was going on, that he wasn't sleeping with someone else. And yeah, Sebastian did that himself, but it wasn't the same. For him it was just sex. But with Kurt nothing was ever just sex. If he was cheating it meant something to him.

Sebastian's skin crawled and by the time he got upstairs he was shaking with anger and couldn't think straight. He opened the door to their room and saw a fire lit and candles all over the place. Kurt was on the bed with a sheepish and almost bashful look on his face.

Something inside Sebastian snapped.

How dare he look so sexy and innocent when he may have cheated on Sebastian in this very bed. And now with the candles and the dinner and everything he was trying to cover it up?

"Who is he!" Sebastian roared and the smile slipped from Kurt's face.

"What?"

"Who are you fucking? You filthy little whore."

After that everything went hazy and red and quick, blood drumming in Sebastian's ears and fury coursing through him. Kurt never did tell him who he'd cheated with. Wouldn't even admit he'd done it. By the end of the night it didn't matter anymore.

By the end of the night nothing mattered anymore.

By morning all that was left was horror for the neighbors to find, and chaos for the police to clean up.