AN: thanks for DeniseSB for beta-ing. Reviews would be appreciated.

Set in Mark, Addison and Derek's intern year. Mark's POV.

Look at me dreaming of you
All I could hope is to have you
To have you walking with me
Laughing so in love, we two
Almost drunkenly I did imbibe of this
Fantasy of you and me

Fool to Think, Dave Matthews Band

"So, are we doing this or what?"

"Huh?" Her question rouses him from the contemplation he's lost in. When he realizes the situation they're in — his body is poised over hers, his now only half erect penis lingering indecisively over her while she looks at him with annoyed raised eyebrows – he fails to stifle a laugh just long enough that she gets pissed and squirms out from under him.

"Hey . . . " he says, consolingly, although he's kind of relieved as he rolls over onto his back, slides off the now unneeded condom and throws it away in the nearby trash can.

"Damn it, Mark!" she sighs. "I could so have been screwing that other guy right now." She wrinkles her brow, trying to recollect. "You know, what's-his-face . . . David . . ." she looks at him for confirmation, then tries again, "Danny, maybe? You know. . .the one that wants to go into pediatrics."

"You realize you're a slut, right Beth?" He pushes her arm gently to emphasize that he's teasing her.

"Oh, and you're not?" she asks.

He likes her. They're friends . . . with benefits. They tried dating a few times in med school, but it didn't work out. But the sex is good, dependably dirty and satisfying and, if there's nothing better, she's fun to hang out with. And now that they're interns in the same hospital, it's sometimes easier to spend the night together than to look for somebody else.

"Sorry," he says. He's not in the least concerned about his lack of performance. If he'd wanted to do her he easily could have. He's just not into it tonight. He's preoccupied. "Sorry I got in the way of your carnal knowledge of what's-his-face." He grins at her and she rolls her eyes at him.

"Whatever," she says, getting up off the bed. "Shit happens." She shrugs and retrieves her clothes from the nearby armchair and, when he indicates to her that he'd like his, throws over his boxers, jeans and over-washed Columbia sweatshirt. He stands up to put on his clothes before sitting back down on the bed. "There'll be other nights, right?" she says. "Or days . . . in the on-call room! Isn't that what the attendings do when they're supposed to be teaching us?"

They both laugh. But the same thought keeps nagging at him and he decides to call on the friendship part of this arrangement and seek her advice.

"You ever been in love, Beth?" he asks softly.

Her eyes widen. "Excuse me?" she asks incredulously. She's on the point of making a joke, but she stops short when he looks at her with a sincerity she's only seen him come close to when the Yankees are being slaughtered by the Mets.

She can't hide her surprise, though. "You in love, hotshot?" she asks.

He pauses for quite a long time before he says, almost inaudibly, "Yeah," and then looks down at his lap, before adding, "I think I have to tell her . . . I have to tell her now or . . ." Or what, he doesn't know. There's just this sense of foreboding; a sense that if he doesn't tell her; doesn't tell his best friend's girlfriend, now, that he's so in love with her it's killing him, nothing will ever be right again.

He stands up, sighing. He's tired and slightly drunk and scared about what he's about to do. "You have any cash?" he asks her. "I used up all mine tonight and I need money for a cab."

She opens her arms wide and shrugs disconsolately. "Nada," she says. "No cash; no nothing. Maxed out my credit card." She smiles mischievously. "I'm waiting for my dad to replenish the supplies on Thursday when we have lunch."

He nods. He kind of envies her easy exploitation of her father. He no longer has anything to do with his family. It was his choice. But sometimes he wonders what it would be like to have parents you actually wanted to have lunch with, or see at all. Right now, though, that's not what's on his mind.

"'S okay," he says. "I'll stop by the ATM." He finds his socks and sneakers, puts them on and then picks up his jacket, bending down to give her a quick, distracted kiss as he makes his way out. "If I see what's-his-face, I'll send him over," he says, by way of apology.

Now he's standing by the ATM completely at a loss and beyond the urge of taking out his frustration on the machine. Not only will it not give him any money, the goddamn thing swallowed his credit card. Fuck! He hates being an intern. For just one second, although he doesn't really mean it, he wishes he hadn't refused the trust fund and other financial shit his family tried to bribe him with. And he hates himself right now for spending what money he has on girls who don't matter to him. He just realized that he's met the love of his life — yeah, the woman who's been dating his best friend for the past year, but he can't think about that now. He has to tell her he loves her. He knows it's a fucked up thing to do to Derek, but he's never felt this way before and he probably never will again and it's just too important to let go of without trying.

He breaks into a run. It's really too far to her apartment, but he's pretty fit and it's doable . . . just. And as he runs—trying to regulate his breath, which is hard because he's thinking about her; trying to regulate his pace, like the track coach always told them, to let the rhythm carry him forward—he sees her face and her hair. He loves her hair and its silky flowing redness that he would love to run his hands through, and he thinks that maybe being able to touch her hair and know that she was his might be the one thing he could do with a woman that would be better than sex.

And he's made it. He's reached the sidewalk outside her apartment. He bends forward, his hands resting against his thighs as he fights to regain his breath in ragged gulps.

"Mark?" It's her! He stands up and looks in the direction of her voice, unable to believe his luck and ready to tell her why he's here. Except the next voice he hears is Derek's. They're sitting together on the front stoop.

"I'm going to ignore the fact that you look like you just ran here and that that makes you insane," Derek says, "because Addie and I have some amazing news." He looks at her and puts his arm around her and she snuggles in close to him and smiles broadly.

Derek shrugs and smiles happily at Mark. "I acted on impulse," he says. "I proposed and Addie said yes and we're going to get married!" He plants a kiss on Addison's cheek and she makes a soft delighted noise in response. "You couldn't have come at a better time, man. It's great that we can share this with you!"

Mark nods and but doesn't say anything. There's nothing to say.

Addison smiles cutely at him and he can't help but smile back at her. "So . . . if Derek's your brother," she says, "I guess that makes me your future sister-in-law."

He nods again. "I guess," he mutters, trying to sound happy instead of devastated, but not quite managing.

"You okay?" Derek asks him.

He finally finds his voice. "Shouldn't have run here," he says hoarsely. "Dumb idea." He shrugs. "The girl I was with bailed at the last minute and I needed an outlet."

He swallows and just about pulls himself together and says, "Congratulations, guys." He walks over to the stoop, briefly pounds Derek on the back and then kisses Addison's cheek. There's a breeze and it blows a stray lock of her hair against his face and, for one moment, he's afraid he's going to freeze and give something away. But he doesn't. He smiles at her and steps back a few feet and everything's fine, as long as he doesn't think about what's just happened, or about her, or anything really. He'll be okay as long as he doesn't think.

"Why are you here, anyway?" Derek asks.

Mark shrugs, trying to buy time to come up with a decent excuse. Because this changes everything; and telling Addison now that she may be the only woman he's ever going to love would truly be a fucked-up and heartless thing to do to the guy he considers his only real family.

"The ATM ate my credit card," he says. "There was another girl that looked like she might be interested, but I need money to buy her a drink . . . you know . . . and I thought Addison might . . ." His voice trails off a little at the end because he can't really be bothered to put any energy into his not very convincing lie. He shrugs again. "I guess I'll just hang with you guys, though." He sighs and he can't help looking one last time into Addison's eyes when he says the words that are meaningful only to him. "It's too late now."