She's with Severide.

He's her partner.

She has no right to be feeling this way.

Erin's thoughts were out of control as she sat in the back corner of Molly's with her boyfriend, Kelly Severide and his friends. She knew she should be happy to be spending time with him because she liked him, she really liked him; but not in the way that she's supposed to.

So instead of mingling and chatting about weekend plans or her day at work, she sat there, sipping her beer every so often and staring at her partner, who was sitting at the bar. And he was not alone.

She watched as Sumner slid her hand up Jay's perfect arms. Arms that she had playfully punched countless times, arms that were for her hands only. The way that Sumner would laugh at almost anything Jay would say.

She watched as Jay flirted back, gently shoving her when she'd make a joke about the little things he did. The little things that before now, only Erin knew about. Or flashing is gorgeous smile when she whispered God knows what into his ear.

She was jealous. And she shouldn't be.

"Babe," Her thoughts were cut off when she heard Kelly calling her name, desperately trying to get her attention.

She breathed in and muffled a quiet "Hmm" so he knew he had caught her attention.

"I asked if you wanted another drink" He said after a few moments, giving her a slightly worried look.

"Oh, um, sure" While she heard him, her gaze was still directed at her partner and the newest member of the Intelligence unit.

"Okay, I'll be right back" Severide sighed and got up from his seat, giving Erin a quick peck on her temple before going to track down Gabby Dawson, the bartender for the night.

When she finally noticed the empty spot beside her, Erin was able to take her eyes off of Jay and looked around the crowded bar for Kelly. After a few seconds of scanning the place, she spotted him at the bar, trying to get Dawson's attention. She noticed a young girl- probably in her mid-twenties- trying very hard to catch Kelly's eye. And though Kelly was paying no attention to the girl, Erin felt no jealousy at all. Perhaps if this girl wasn't a drop dead gorgeous, straight out of a Victoria's Secret catalog model it would make sense, but in Erin's eyes, the young girl had no flaws, and it confused Erin as to why she didn't feel threatened.

She thought maybe because she knew Kelly only had eyes for her. Or maybe it was because they were passed that stage, the stage where the worry of losing one another wasn't an issue anymore; because they felt comfortable with each other. The only other possibility that made its way through Erin's brain was Jay. She knew she had feelings for Jay, and she tried to push them aside, but the pain she felt when Sumner touched Halstead's arm was far worse than when this young girl pressed her entire body against her boyfriend, her boyfriend.

That's when she realized, she didn't only have feelings for her partner. She was in love with him. There wasn't anything she could do about it, especially not now, with Sumner all over him.

The worst part of it all was that she would have to break up with Kelly, maybe tomorrow when this pain in her chest is gone. After having some time to go through everything she was thinking about in this moment. She wanted Kelly to be the one, it was so simple with them. They don't work together, Voight has no problem with it (professionally anyway), and she truly did care about him. Not wanting to think about it anymore, Erin got up from her stool just as Kelly was returning.

"Where are you going?" He asked with a soft tone, not accusing- just legitimately curious as to where she was going.

Clearing her throat, Lindsay said, "I'm really not feeling to well, I think I'm gonna head home."

Severide could hear the sadness in her voice and offered to give her a ride home, but she declined. "I think I'm just gonna walk, you know- clear my head?"

He understood. He wasn't blind. He saw the way Halstead had been flirting with that girl all night, and the look in Erin's eye that he'd never seen before. Everyone could see that there was something there, even if neither of them acted on it, including Kelly. "Yeah. Okay, I'll call you tomorrow?"

Nodding her head, Erin answered a weak "Sure" and walked out of the bar.

Jay had been trying to get away from Sumner for about 45 minutes now, but she kept going. Sure, at first it felt good being flirted with a little, especially since he couldn't flirt with Erin as much now that she was with the firefighter. He got bored pretty quickly though, Sumner is hot, there's no denying that, but she's not Erin. He was starting to get quite annoyed if he was being honest. Sumner wouldn't stop talking and she would laugh at everything he said. Just as he started to phase out what she was saying he heard her bring up Erin's name, "-I mean, I get that she's had a hard life, but she really needs to stop shutting people out." She stopped talking to take a sip of her Long Island Iced Tea, but started right back up again, "I just feel so bad for her-", and that's Jay had had enough.

"You know nothing about her. You've been here what, 2 weeks? Erin can be closed off, but that doesn't change what an amazing person she is. She's been there for me when no one else has. When everyone around me is dropping like flies, she's always there for me. Her 'hard life' shaped her to become one of my best friends, and you, you have no right to be talking shit about someone you just met." Jay was livid, fuming. Taking a breather, he looked up to where Erin had been sitting, only to notice she was gone. What stuck out to him though, was that her boyfriend was still there, acting as if she'd never been there at all.

Jay abruptly walked away from his new coworker to find his partner. As he approached the table where Severide, Casey, and a few other firefighters were sat, he asked where Lindsay went.

Unexpectedly, Casey answered, "She went home- said she wasn't feeling too great." After hearing that, Jay looked to Kelly, who just shrugged and continued drinking his beer.

Jay knew something was up, so he grabbed his coat and headed over to his partner's apartment that was only a few blocks away from Molly's.

After Erin got home, she stripped off her jeans and combat boots, and slipped into some pajama shorts and one of her old t-shirts from the academy. She switched on the TV, grabbed a cup of coffee, and just had a moment to relax.

She was almost asleep on her couch when she heard a faint knock on her door. Thinking it was Severide, she dragged herself off the sofa and answered her door. Surprisingly, it wasn't Kelly, but the one person she really needed to see.

"Hey" He said as she stepped aside to let him inside her spacious apartment.

"Hi." She said, with little emotion in her voice. "What are you doing here? What about Sumner?"

Jay laughed a little bit at the way she said Sumner's name and said, "Sumner? The girl wouldn't leave me alone. I almost had to pry myself out of her grip to come look for you."

"You mean to tell me what I saw back there was not you trying to get in her pants?" Erin asked with an amused grin.

"No, pretty much the exact opposite. It was sort of like when you get gum on your shoe, and as hard you try to get it off, it doesn't budge and sticks to you wherever you go." That got a laugh out of Erin, but it quickly disappeared when he added, "Why, you jealous?"

Jay didn't mean it literally, he meant it the way they always joked around. He figured he'd get a "you wish" because it's their thing, but Erin's demeanor suddenly changed, and he was the cause. "Wait were you," he paused, "actually jealous?"

That question shocked Erin and she didn't quite know how to answer it, "No. Yes. I-I don't know" She sighed, and buried her face in her hands.

Jay noticed how disheveled she looked, and walked up to her, grabbing her hands and interlacing their fingers. "It's okay to be jealous, you know?"

"No; it's not" She looked up at him, just now realizing how short the distance between them actually was. "I have no right to be jealous, I don't own you."

He laughed again, not knowing where this conversation was going to lead, and looked down to her, "Not yet…"

Erin continued looking at him, her eyes shifting from his lips to eyes and back, before leaning up and pressing her lips to his. Taking the risk that both of them had been afraid to take since the moment they met.

It took a moment for Jay to realize what was happening, but as soon as he gathered his thoughts, he kissed her back.

The kiss became more heated, and they were both fighting for control. Jay slipped his tongue into Erin's awaiting mouth and she pushed hers into his. This was a battle that neither wanted to lose, but the need for air finally caused Jay to pull away. Before continuing, Erin looked at Jay with lust filled eyes and finally told him how she felt. "I think I'm in love with you."