Disclaimer: I don't own Grey's or the characters.

You Are My Sweetest Downfall

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - What Derek didn't know had never hurt him, but it had hurt Mark more than any of the two of them would ever know. He'd been forced to stand along the sidelines for almost sixteen years, watching as they got married, contemplated children, took vacations together, and finally slipped into the slums of indifference.

It wasn't Derek that had met Addison first, it had been Mark. They'd been partnered up for a microbiology lab and Mark had been awestruck by the beautiful, willowy redhead who still occasionally fumbled awkwardly like the thirteen year old band geek that only she knew herself to be. It had taken him two platonic lunches after lab dates and a couple sessions of studying for prelab tests before he convinced himself to ask her out.

Her cheeks had grown bright pink and he'd caught a sparkle in her eye as she looked downward and bashfully accepted. She would never admit it but he'd been her first date (excluding Skippy Goldberg, who she'd never really counted as a real date) and the simple fact that a boy as attractive as Mark Sloan had taken any sort of interest in her was almost enough to send her into a series of arrhythmias.

She'd changed three times that night before settling on a pair of simple black slacks (that accented her slender legs and curved bottom perfectly) and a tactfully low cut, blue silk top with black stilettos. He'd arrived five minutes late and as Addison answered the door she tried to repress her insecurity over the fact that he'd been late and she'd thought that he wasn't going to come at all.

He'd presented her with several daisies which had made her blush again and she'd fussed over them, setting them in a tall vase, pretending to ignore her roommate who was grinning and trying not to roll her eyes.

He'd smiled reassuringly as she slipped into a light jacket before taking her hand gently in his and leading her out to the car. He'd fiddled with the radio and the heating, unsure as to what she liked, but deciding that her slightly tense smile was a result of nerves and not a reaction to some heat wave he couldn't feel, so he left it alone after a few moments and tried to initiate small talk.

Once he got her chatting he was surprised at how open she was and by the time they'd pulled up in front of the restaurant he knew she had three older brothers, a father who'd passed away suddenly when she was thirteen and a pretentious mother who'd shipped her off to boarding school when she'd hit the acceptable age.

As he escorted her out of the car he noted that she was much more relaxed and returned his smile as he picked up her hand again. He'd called ahead for a reservation so they slipped in behind the hostess and followed her to a table for two just next to a window that overlooked the city.

"It's nice out tonight." He commented absently and she agreed.



He was again surprised at how easily conversation came for the two of them and as he watched her fiddle slightly with the golden clasp of her bracelet, or twist a strand of brilliant red hair around her finger before tucking it behind her ear, or even tug at the dip in her top (the years of catholic boarding school firmly imprinting on her mind that indecent exposure was something that was severely frowned upon) he wanted more. Not necessarily sex, though he was never one to turn it down, but he wanted time; time to be with her and find out more about her, to pick up on her ridiculous habits and gently mock her for them. He wanted to be able to recognize the smell of her conditioner or the dab of perfume that she pressed just under her jaw line, to see if she was one to wear a baseball hat with a t shirt and jeans on a Saturday or whether she remained in the Prada and Gucci he'd watched her sport around campus.

Maybe it was that he was tempting fate with his thoughts, or perhaps it was by sheer coincidence, but at the next table over he caught a glimpse of a familiar face and a familiar wave,

"Mark!"

He grinned widely, "Derek, hi."

He was sitting at the table across from them with a date who looked unbelievably bored, her chin resting in her palm, looking forlorn as she listened to Derek talk animatedly about Broca's area.

Mark waved them over and a helpful waitress pushed the two tables together so the two couples could share a meal. Addison had suddenly reverted back to the shy, timid girl he'd picked up so he took the liberty of introducing her,

"This is Addison."

He caught the look that both Addison and Derek shared as they caught a glimpse of one another, and immediately felt his heart sink. Addison extended her hand and smiled widely,

"Nice to meet you."

The way he was looking at her, Derek might as well have slipped an engagement ring on her fourth finger and escorted her to the nearest church. Instead her took her hand and gave it a slight squeeze,

"You too."

Derek's date snorted slightly and placed her napkin on the table, "Nice to meet you all, have a good night."

Derek didn't even have the grace to look disappointed or sorry as she picked her coat up at the coat check and stalked out, clearly hoping that she wouldn't be going home alone and wistfully remembering dates that hadn't revolved around the anatomy of the brain.

Mark slumped back in his chair and offered the occasional, half hearted supporting smile when either of them looked over in his direction. Inside he wanted to die, as he watched his best friend interact with 

the one woman who'd ever meant anything more than physical since his "girlfriend" in kindergarten he knew that he didn't stand a chance.

Afterwards, when he dropped Addison off at her residence, she looked incredibly guilty.

"Mark, I..."

He shook his head and forced a smile through his gloomy thoughts, "It's ok. He's a good guy, he'll treat you right."

She looked inquisitive as she asked, "Yeah?"

He nodded, "Promise."

"I'm sorry this didn't work."

He ached to tell her that it could work, if she could just push Derek out of her thoughts for a moment he could make her forget about him for the rest of her life. Instead, he shrugged meekly and said,

"What can you do? Hey, I'll see you in Micro on Monday ok?"

She nodded eagerly, hoping that this wouldn't cause a rift in their blossoming friendship, "See you then."

As he turned to leave he caught sight of the daisies on the kitchen table and sighed slightly, shoving his hands into the pockets of his leather jacket and returning to the grey Camaro. He drove to the nearest bar, fuming inwardly that life wasn't fair and that he should be planning his next date with Addison instead Derek.

Still, when Monday came and he was forced to work with Addison on their latest assignment he felt strangely settled as they spoke lightly and bantered playfully over their Bunsen burner. He felt slightly hopeful, maybe if he stuck around Derek would lose interest and he could sweep in and save the day. Somehow he doubted it but it couldn't hurt, could it? Why lose two good friends over ten minutes where he'd thought he might have found "the one".

So he stuck it out, he became the best man and the best friend. He joined them both on several vacations and they joked about putting in a "Mark room" in the Brownstone instead of a baby room. In some sick and twisted way it made him happy to see Addison so happy, and it was that thought that kept him out of her bed for the longest time.

Then came the indifference. He became the one taking her out for dinner when Derek stood her up, he was the one who picked up Derek's cell phone to try and settle her down when he'd promised to be home hours ago. He began spending more time at their house, jus to make sure that she was alright. Several times she'd blown up at him, blaming him for their problems, and he'd obediently left the house only to find her sobbing quietly in an on call room that next day.



On night it became too much and he was sick and tired of seeing her in so much pain, he was fed up with Derek for effectively destroying the only (potential)true relationship he'd ever had. So that night when he brought over Chinese and a movie, looking guilty as he told her that Derek was planning on staying overnight at the hospital, he didn't push her away when she leaned in to kiss him. It wasn't the first time she'd tried it but he'd refused to reciprocate, not willing to demolish his friendship with Derek. Now, he didn't care what happened to his best friend, he no longer had the excuse that Addison was happy to keep him out of her bed. He no longer had any excuse. That night, when Derek found them in bed together Mark couldn't even bring himself to apologize. As he walked by him he shook his head and snarled,

"Don't you dare blame this on me. This is you, all you."

A couple years later he perched on the edge of the hotel bed, wearing only a white towel. Addison sat in the conveniently supplied chair, rocking slowly back and forth. She looked up at him and he could see the raw hurt in her eyes. She continued rocking for several minutes until she stopped abruptly and her eyes met his again,

"You promised."

"What?"

"You promised he was a good guy, you promised he would treat me right."

He frowned, desperately scrambling to remember when he'd said that before settling on the night of their first and only date (excluding sexcapades),

"Oh." Was his only reply.

He hesitated a moment before rising and scooting into the chair, shifting her over a little bit. He wrapped his arms around her and she leaned her cheek onto his chest. He could feel the tears dripping onto his bare chest and tilted her chin upwards, kissing her softly, chastely,

"I can fix this."

She sniffled slightly, thinking her was talking about her relationship with Derek before realizing her was talking about her, her own brokenness.

"Mark..."

He squeezed her a little harder and kissed her again, this time pressing a kiss into her damp tresses,

"Just let me try."