Sevasey One Shot

He's Mine

Summary:

Lieutenant Kelly Severide has a reputation for being a player and hopping from bed to bed—it's not true, but no one needs to know that—and it was all okay with his (secret) boyfriend until someone threatened to take what's his away from him.

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What is unbeknownst to almost anyone from the firehouse is the relationship between their two lieutenants. Everyone knows their history—well, part of their history. Matthew Casey, Kelly Severide, and Andy Darden had been a trio from the start of the academy. Breaking records—that still hasn't been beaten yet—and causing a bit of mischieve from time to time, but overall being amazing students. They were passionate about their future careers and were in it for the right reasons. They didn't gloat about their successes, they didn't shove anyone down to get to the top, and especially they didn't get in over their heads. But the most important part of their history is the friendship from the academy.

That sounded cheesy, but it's true.

Kelly Severide and Andy Darden had been best friends since childhood, but they once saw the blue-eyed blond that looked too small, frail, and young to be in the academy. They had immediately taken the blond under their wing, especially when it was revealed to everyone in the school's locker room who Matt's parents were. What came out of that encounter was a strong brotherhood that is still alive to this day.

The only time Andy got cocky was when Matt and Kelly finally stopped dancing around each other, kissed each other, and then started a relationship. He was the one who came up with the plan to lock them in the closet and "accidentally" had to leave because Heather needed him. Three hours later, when he came back, Matt was on Kelly's lap with his head tucked underneath Kelly's chin, and they spoke softly. It took awhile for Andy to stop grinning like a madman at the two of them whenever they acted couple-ly around him. That only stopped when he had walked in on the two of them having sex on the couch, and Andy swears that "it had scarred my mind forever and I can never go back to the innocent boy I was," to which Kelly rolled his eyes and threw a pillow at him.

They had kept their relationship a secret from the academy because they didn't want their relationship to taint the rest of their careers. They tried to get placed in a good house during their candidacy and then worked their way up so they had enough experience to their name to be able to transfer to the same house.

It was hard for them to be in the same classes and with each other almost every hour of every day and not touch or kiss or talk too closely for it to be considered amicable, but they did, and it was worth it. They were all placed at different houses, sadly had different shift patterns and rarely hung out as a group as much as they used to. Kelly and Matt had their own apartments since they worked on opposite ends of the city, but it was often one of them being over at the other.

When they were no longer candidates, they requested a shift change and ended up on the same shift, and they would go back to hanging out with each other whenever they could.

Their relationship became better when the three of them got transferred to Firehouse 51 on the same shift, and it only got better when Casey and Severide worked their way up to Lieutenant of their respective truck.

So Matt, having been with Kelly for a little over ten years at this point, is well aware of the reputation that somehow got stuck to Kelly. He knows Kelly hasn't cheated on him, and he knows that Kelly isn't trying to flirt with anyone; his friendly nature just gets perceived in a flirtatious manner. He finds it amusing at this point, sitting beside his significant other and watching other people trying to hit on his man knowing full well that Kelly is only going home with him and no one else.