Chapter 1:

Prompt/Inspiration: Rumour Has It by Adele. Specifically the lyrics, "I heard... you've been missing me / You've been telling people things you shouldn't be / Like when we creep out and [he] ain't around / Haven't you heard the rumors?"

Author's Note: Hi, guys! I started this whole idea a little while ago, with this small fic called "After." (You might want to read it before starting this one; you can find it on my page.) I just wanted to quickly mention two things: 1. all of the italicized parts are flashbacks and all of the regular stuff is narration 2. this first bit takes place where the season finale left off. Everything should be back up to real time in the next chapter. :) Enjoy!

. . .

"Lexie?" Mark asks, opening the door to see her standing in front of him. "What are you doing here?"

"I lied," she tells him.

"What?" Mark breathes, feeling his heartbeat quicken and his hopes soar against his better judgment.

"About what I said before, not wanting to love you, I lied." She takes a breath. "I always want to love you."

Mark stares at her in awe. "You do?"

"Yes," Lexie whispers. She steps closer, looking him up and down. "And I've—I've missed you, Mark." Her breath catches as she utters his name, but she ignores it. "I've really missed you."

"I've missed you too," he replies, reaching out hesitantly to hold her wrist. Lexie shifts her arm within his light grasp, moving to hold his hand securely with hers. She looks up at him, her eyes a deep and dark brown, and asks one simple question that would snowball into years of misgivings.

"Can I come inside?"

. . .

…And that was how it all started. She appeared at his door one night and then never stopped appearing. He let her in that first time and then was never able to turn her down again. Things, of course, had changed since that opening encounter, but there were hardly any nights in those first few years that were different. She would always show up (unexpected, as Mark and Lexie liked to tell themselves) during the night, after she'd slipped away from Meredith's house and the man who would later become her husband.

She would materialize at his door as if she'd just teleported there, and knock softly, trying not to make the slightest noise to wake the neighbors. He would usher her inside, an easy smile lighting up both their faces when they were finally together again. After time, even the knocks would prove to be unnecessary, as she soon had her own key, hidden amongst the other and much less meaningful gold-colored metals on her key ring. When things progressed to Lexie letting herself inside, Mark would make sure he always appeared busy just around one or one-ten at night so as not to give her the idea that his whole schedule revolved around her. He would always have a medical journal handy or the TV on so as not to give her the idea that his whole existence revolved around her and only her. That would be too much. There'd be no going back after that. And as much as Mark didn't want to go back, he wasn't sure he could handle it. So he allowed fate to be the dealer and let the cards fall where they may.

But even back then, part of her knew how much he looked forward to those visits. Mark was sure she'd never know the whole story, but for Lexie, knowing part of it was enough. Just knowing that he planned out these long stretches of happiness just as she did was a comfort. To know that she wasn't alone in her obsession was more than she could ever hope for.

. . .

There's a quiet knock on the door. Mark exhales softly, walking slowly across the room to answer it. He opens the door and is in no way surprised by who he sees standing in front of him. In truth, he had wanted her to come. But another part of him had wanted her to stay away. Things were permanent in her life now; she didn't need him. Or so he tried to think.

"Hi," Lexie smiles at him. Her voice is a sigh of relief—she's been waiting, desperate to see him, for weeks—but Mark looks anything but relaxed. He meets her eyes, both his expression and body language remain guarded as he holds the door only partway open.

"What is it?" Lexie asks, noting the look on his face with worry. Mark nods towards the ring on her left hand.

"You're married now, Lex," he whispers hoarsely. He swallows, not wanting her to see how hard it was for him to say those words aloud. "That makes this different. It makes this serious."

Lexie stares at him. It's always been serious, she wants to tell him. "I know," she replies instead, holding her breath, waiting for him to send her away.

"That makes this adultery, Lexie," Mark presses, taking her hand lightly when he sees she's reaching out for him. He squeezes her fingers for emphasis. "Are you sure you can handle that?"

"I don't have a choice," she whispers. Mark nods in understanding, letting his eyes close briefly. Since the first night she ever showed up at his doorstep—stripped naked and uttered the words "teach me"—he hasn't had a choice, either. And up until now, he's never questioned that fact. He's never wanted to; he's never felt obligated to.

"Okay, then," he replies, drawing her inside and shutting the door softly. He steps towards her, dipping his head down to her level. "If you're sure," he whispers across her lips.

"I'm sure," Lexie replies, her body arching up to meet his as she twists the ring off her finger. "I've always been sure." She lets the discarded band fall to the floor, where it's forgotten in seconds as he draws her deeper into the apartment.

. . .

During that single night, a hundred different firsts happened to Mark and Lexie. They were both experiencing such loss and gain simultaneously that it was impossible to pull the two sensations apart. All Mark knew was that he was losing her to someone else, and all Lexie tried to do was prove him wrong.

With every touch, every word, and every kiss, Lexie tried to show him that he was the one she was truly in love with, even if a flimsy piece of paper and a church full of witnesses said different. Every time she kissed him, every time their bodies met, she tried to make it clear that there was a reason she'd showed up on his doorstep. She could only hope he would grasp it.

Mark, on the other hand, was trying desperately to hold onto her. He knew now that their time really was slipping away—how many more visits like this would occur until she finally left him behind and went with the better guy? Mark didn't want to waste a thought on it. Not while she was here, in his arms, telling him she loved him. So to lengthen the night, he said the same to her. Each time she touched him, he'd hold her close and fail to let go. Each time she kissed him, he'd kiss her back until they were both literally breathless. Each time she spoke, he would hug her to him, making sure her words went directly in one ear and never left through the other.

Mark had never held Lexie closer to him before this night, for he had never wished to be as close as humanly possible to her. He had never made love to her as sweetly or as gently as he did that night, nor did he do so without such shaking fingers and ragged breathing. She had tried to calm him down, to assure him that she was there with him, but there was nothing she could do to help him. Because she wasn't there with him, not really, and she would never be.

The process of not registering that one small fact took all of his willpower and then some. All he wanted to do was live in the here and now, and not give a damn about his blackened future.

Throughout that seemingly endless span of hours, Lexie lost count of how many times he'd told her he loved her; she lost count of how many times she herself responded with a tearful repetition of his own words.

During that night, they loved each other. Truly, they did. During that night, there was no one else and nothing else, just a pair of people and a long-gone yet still hoped-for lifetime together. Neither Mark nor Lexie had ever felt more connected with another person—or each other—before or after that night. That quiet evening in April always hung above all the others, bittersweet to the highest degree.

. . .

Lexie had gone home, early that spring morning, crying so heavily she broke her cardinal rule—waking up Jackson. He'd asked her, scared and worried, what was wrong—why was she out so late, where had she been, and what had happened. Lexie had lied, naturally, and said there were problems with her family. And Jackson had accepted that and comforted her through an endless stream of tears. Family was a topic they never touched, for Jackson always assumed she had the same relationship with her father that Meredith did—the same relationship he had with his own family. He thought it best to steer clear.

Mark had cried as well, though there had been no one there to ask him what was wrong or to try and slow the flow of his tears. He wasn't sure he wanted anyone there. Well, he could think of one person he wanted, if he was being honest with himself, but thinking about her simply made his throat constrict painfully. He didn't like to show weakness, especially concerning something he had no power over. Someone he had no power over. So, Mark had cried alone, and, eventually, when he managed to pull himself together, forgot the experience altogether. He pushed it from his mind just like he believed she'd pushed him from her mind and he moved on. He got back on his feet and braced himself for his next fall, for he knew there was always one coming while he lived in this precarious half-life he both hated and loved.

And he wasn't wrong. Just a couple weeks after Mark and Lexie had shared one of the most indescribable nights of their life, she moved away to make a new life with her husband. She had essentially left him behind, but she only did so because she had no way to bring him with her. Desperate, Lexie had even inquired at OHSU, the hospital and university that was her new workplace, if there were any other positions available within the Plastics or ENT departments. She knew the insanity of her wishes, but still it didn't stop her. If at all humanly possible, she wanted Mark as close as he could be. But, of course, there were no positions. In a major metropolitan hospital, with thousands of employees, she and Jackson were both lucky to even get jobs.

. . .

Mark didn't speak to anyone for weeks. In a stroke of what he unwillingly called luck, he had lost his most important patient the same week he'd lost the most important person in his life. So at least there was an explanation in plain sight for Derek and everyone else to see. No need to dig beneath the surface of concerned surgeon, Dr. Mark Sloan.

When he managed to think about something besides her, Mark felt genuine gratitude for this. Of course he felt awful about losing his patient, but somehow the alternative seemed even worse… If there had been nothing to distract Derek and Meredith, he was sure they would catch on. He was sure they would notice how he slept less than four hours a night for over a week since she'd left for Portland. He was sure they would be able to see the sadness in his eyes and attribute it to the loss of an ex-girlfriend. He was sure they would be able to tell.

So, for the first time in his life, Mark Sloan was happy someone died under his watch. It gave him the excuse to die himself.

. . .

For Lexie, the opposite was happening. While he lost sight of her more and more everyday, Lexie constantly saw him hiding in the edge of her vision. A doctor here, a patient there—it seemed like everyone resembled Mark when, in reality, Lexie was sure they looked nothing like him. Desperate times call for hallucinations, Lexie had thought bitterly.

For her, he was never as far away as he was in reality. Any time she let her mind wander, he was always there. Anytime she lay awake during the night, unable to get to sleep because her midnight excursions had ruined her sleeping schedule, he was there. And anytime she thought of the person she loved, he was there, standing alone, with no runner-ups.

You can't have more than one true love, after all.

. . .

"Did you ever think of being anything besides a doctor?" Lexie asks, her head resting on his shoulder, late one winter night.

"Oh yeah," Mark replies, stroking the skin of her hand with his thumb. He kicks off his shoes, propping his socked feet up on the footrest in front of them. "I wanted to be a firefighter when I was ten."

Lexie laughs, turning her face into the collar of his shirt to muffle the sound. She's grinning when he can see her expression again. "Oh, you would have looked good in one of those calendars," Lexie snorts.

"Hey, I could have made it happen," Mark tells her. "I'm a big, strong guy."

"Oh, yes," Lexie replies gruffly. "Very big. Very strong."

"Are you mocking me?" Mark grins, twisting his head to get a good look at her.

"Nope," Lexie answers, giggling.

"I'm telling you, it could happen."

"Sure it could," Lexie smiles.

"I'm telling you," Mark repeats. "One of these days, you'll be caught in a fire, only to be saved by me." He grins. "And then you'll ask me, all surprised, 'Mark, when did you become a fireman?' And I'll say, 'I've always been one. It's my secret passion'."

"Is it?" Lexie grins, tilting her head from its resting place atop his dark sweater to get a good look at him. Mark nods, but there isn't a smile on his face when he meets her eyes.

"One of many," he replies softly, staring into her eyes.

. . .

As the years went by, and as their time together became less frequent and more precious, they began having sex less and less. …Until, eventually, they stopped having it altogether. After she moved away, they both thought that they'd go crazy without the touch of the other on a regular basis—but the opposite happened.

Instead of wishing everyday that he could feel her skin against his, instead of hoping everyday that he would fly out and meet her in one of the hospital's on-call rooms…Mark and Lexie simply savored the shorter and shorter times they were able to have together by acting like they weretogether. They sat together, ate together, talked together, laughed together—they acted like a bona fide couple. Except for one simple, yet immensely powerful fact:

They were not a couple.

They were not together as boyfriend and girlfriend or husband and wife. They were even no longer together as adulterer and adulteress—in the sexual sense, at least.

Mark and Lexie held no claim to each other except what they felt in their hearts, which, of course, would not be enough to convince anyone. It wouldn't convince their coworkers, their friends, or, god forbid, their families. It wouldn't convince Jackson, Meredith, or Derek. Their feelings for each other couldn't even make a big enough argument to convince themselves that they belonged together, so why should they try to convince anyone else?

They had each other, for however brief a time, and for now, that was enough.

. . .

Author's Note: I'm sorry that was short and filled with narration. I know, annoying. But I'm just setting up the background information here, the real stuff (dialogue, etc) will come soon. Thank you for reading and I hope you come back. (Oh, and don't forget to review please! They make my day and I love hearing what you guys think!)

PS: A huge thank-you to the wonderful Paige on tumblr for giving me the song that worked as inspiration for the title of this fic. Seriously, if she hadn't intervened, this thing wouldn't be published for days. ;)