Today was supposed to be a good day.

Today was supposed to be an easy day.

The case wasn't easy, per se, but he knew at the end of this extremely long shift that he would be able to go home and curl up with his girls. And, he would tell anybody who would listen that he was really looking forward to that.

Today was not supposed to include a best friend and an ex-boyfriend monopolizing most of his girlfriend's time.

Luke Alvez was not jealous, that is something that he knew for certain. Jealousy was absolutely not the reason that he was currently pacing in front of her office while still dressed in his kevlar vest. Jealousy was certainly not the reason his heart was beating faster than it had when he was chasing down the UnSub. And, jealousy was definitely not the reason that he was glaring at the partially closed door while hearing her giggles filter into the hallway.

"Hey, Luke..." Matt said, announcing his presence to the pacing man as he turned the corner, stopping short at the sight of his co-worker. "What's eating you?"

"Nothing," Luke says, glancing over at the other agent before turning back to the black door with a glare. He pauses when he hears her breathy voice exclaim Kevin's name. Luke looks over at Matt, wondering where the growling was coming from before realizing that the rumble was in fact, coming from his own mouth.

"It's just Derek." the other man announces, clapping his hand on Luke's shoulder as he continues past him towards the bullpen.

"And Kevin," Luke mumbles, rubbing his hand across his jaw. Listening to the soothing sound of his calloused hands rubbing against the stubble littering his face. "Kevin..."

"You don't have to be threatened by Kevin," Matt replies, turning back to Luke in the hallway, with a smirk.

"Threatened?" Luke repeats with a scowl. "I'm not threatened by...that's ridiculous..."

"Right," Matt counters with a chuckle, "So take off the vest and go see your girl, I'm sure she misses you." Luke nods, walking to the door and stopping short with his hand pressed flat against the front of the door before turning and walking quickly down the hall.

Luke Alvez, was not threatened by an ex-boyfriend, especially not one that loved his girlfriend enough to propose. The sheer thought of her wearing someone else's ring did not cause a thin layer of sweat to break out on his forehead. It also, did not, cause his heart to begin beating extraordinarily fast in his chest. That same thought did not send him into a panic as he stared at himself in the bathroom mirror. And it definitely did not cause him to rip off his kevlar vest and unbutton his shirt because he felt like he couldn't breathe. No, that was preposterous, he doesn't have panic attacks. And, Luke Alvez doesn't ever feel threatened.

"What's up, Alvez?" the Hispanic man turns his hand to stare at the man who entered the bathroom while he was staring at himself. Luke finds himself nodding, quickly locking eyes with the man in the mirror. "Penelope has been asking for you."

"Thanks," Luke replies, reaching out to wash his hands and pick up his vest.

"Alvez, you don't have to worry about Kevin, Penelope doesn't want him." The dark haired man pauses on his way to the door with stiff shoulders.

"Worry, I'm not worried," Luke responds, reaching out to yank on the door handle.

"Sure..." Morgan yells after him, the last thing Luke heard before the door snapped shut was the boisterous laughter of the other man.

Luke Alvez was not worried. In fact, he hadn't worried in years if he was being honest with himself, which he wasn't. But the thought of being worried had nothing to do with the fact that he had positioned himself outside of her office with his arms crossed over his chest, and his face set into a scowl. Worry was not the reason his blood was boiling at the thought of Kevin being anywhere near his girlfriend. And worry was definitely not the reason, he was shaking at the thought of their previous relationship, choosing instead to ignore anyone who was in her life before him.

It wasn't the fact that he knew exactly what she looked like when she smiles brightly at a man, making that person feel as if they were floating on top of the world. It wasn't the fact that Luke knew exactly what it felt like to be loved by the most genuine person in the world, making that person feel as if they were the only person in her life. It wasn't the fact that he knew exactly the sound she made after she had been so thoroughly kissed that her bones weakened and turned to putty in his hands. And it wasn't the fact that he knew he loved her from the very moment he saw her two years ago.

It wasn't all of these things combined that caused the man to push himself off of the wall he was leaning against and race to the door of her office. It wasn't all of these things that caused Luke Alvez to push the door open and stroll over to the woman with a purposeful stride, reaching out for her hand and pulling her into his arms. It wasn't everything that he was currently feeling that caused the man to grip her face between his hands and pull her lips against his in front of her best friend and her ex-boyfriend, silencing the surprised squeak she admitted to being swept off of her feet. It wasn't the fact that she felt extraordinary in his arms as she relaxed and opened her mouth to allow his tongue to battle with hers, that caused him to keep kissing her, walking her back towards the door. It wasn't the sound of her breath leaving her body when her back connected to the doorframe that caused him to kiss her harder.

No, it was none of these things he realizes as he pulls away from her and presses his lips to her forehead with a calmed heart and steady breathing.

"Are you jealous?" Penelope asks with her eyes closed, he shakes his head and presses his lips to hers again.

"Territorial," he answers before kissing his girlfriend again. "there's a difference."