A/N: this is a random idea that suddenly made itself known this morning, and I ended up writing this. I'm not entirely sure what I make of it myself- so do let me know what you make of it!

Matthew subconsciously swirled the champagne around in his glass as he looked around the gallery. While he enjoyed art, black-tie exhibitions in expensive West London hotels with a horde of attention-seeking socialites in attendance weren't exactly his preferred mode of appreciating paintings. Still, the hotel was a client of his firm's and he was only doing his duty by turning up. Plus, there was a free dinner…and other attractions.

He slowly meandered through the large room, grinning amusedly to himself at the fragments of pretentious conversations he overheard as he did so. Most of these people had no idea what they were talking about, but were gifted with the confidence that ignorance brings.

His smile faltered as his eyes fell on her.

She was like a jewel in the room. How hadn't he noticed her sooner? Her petite, yet curvaceous, frame was draped in the most beautiful gown he'd ever seen. He almost laughed to himself- of course she would be dressed in the finest dress that London fashion had to offer. Her taste was exquisite; and unparalleled, as evidenced by the small group of photographers encircling her wherever she moved to. The whitish-silver silk of the gown was covered in tiny beads of the same colour, catching the light in just the right way and illuminating the room.

Matthew's eyes darkened as he noticed the thin, string-like straps, precariously resting on her shoulders; he thought of how little effort it would take to nudge them off, and slide them down her arms… He took in the way the material skimmed across her breasts, revealing just enough to whet his appetite. His eyes settled upon her hair, styled in loose but neat waves, practically inviting him to run his hands through it- and the memory of her hair splayed on his pillow as her head rolling around in ecstasy invaded his mind.

He turned his attention to the painting nearest to him and sipped his champagne, in an attempt to dampen the feelings burning inside of him.

Mary smiled politely as the clicks of cameras echoed around her. They were obviously expecting her to stop and pose, but she hoped that by pretending to intently examine the artwork in front of her, they'd take a hint and focus on Prince William's second cousin- or whoever that girl in the ludicrous mini-tiara was. Apparently, however, even a side-profile of her was preferable to a full-on snap of Lady Alicia, and the cameras continued.

Mary turned so that her back was to the photographers, sighing as she realised she'd just given them a new view of her one-of-a-kind Alexander McQueen.

All annoyance dissipated at the sight of him. She hadn't been sure he'd turn up. It wasn't really his scene, to begin with. And then there was the issue of…them. Things had grown a little complicated recently. Did he come to see her? She doubted it. He wouldn't have chosen such a public place to see her for the first time since last week- he'd come out of duty to his work. That's all.

Still, she couldn't help her mind wander as her eyes raked over him. The first thing she noticed was that his tie was askew and the knot was far too tight. She laughed inwardly- he hadn't been formally taught how to tie a proper knot, as all the other men here had. But then her mind took her back to last week, and conjured up the memory of her removing it from his neck as he kissed her, and all that it had led to, for the first time. Her eyes travelled down- registering how well his crisp white shirt clung to his lean body- before settling on his belt, and she wondered whether this one would be as difficult to unfasten as the brown one had been.

She watched him raise his glass to his mouth as he read one of the captions next to a sculpture. Her heart fell as she saw the glint of light coming from his hand- from the ring that somebody else had placed on his finger.

Matthew peered over after a few minutes, only to find that she was no longer there. He looked around quickly, mildly panicked. She couldn't have left.

He perused the room until he finally spotted her in the corner, perched on a stool, surreptitiously scrolling through the phone which she should have turned off at the beginning of the evening, in accordance with the requests of the hosts. Matthew grinned as he felt a surge of affection at her naughtiness.

"I'd be careful if I were you. They might kick you out."

Mary's head shot up at the sudden sound of his voice, the actual words registering only moments later. She smirked as she realised what he meant. "Well they can't expect me to resist checking Twitter every once in a while if they're going to lock me in a room full of dullards."

"What are you talking about?" Matthew feigned disbelief. "I just heard someone class Picasso as an Impressionist. I defy you to find this level of insight and expertise anywhere else." He joked, even as he tried to remember what it was like to catch the soft skin of her cleavage between his teeth.

Mary giggled happily, and he cherished the sound- it being one that only he was able to produce. "I've obviously been remiss in doing the rounds. Although it would be difficult, anyway, with all these stupid photogs chasing me around."

"Poor Mary." Matthew tutted mockingly. "It must be so difficult having to endure glamorous event after glamorous event. Maybe you should be glad that you're getting so much coverage for your family." He baited.

"Are you glad that your firm sent you here to schmooze your client?" Mary challenged.

"I am now." Matthew answered without hesitation, his voice suddenly low.

Mary's breath hitched at the intensity with which those blue eyes were staring at her. She dropped her gaze, to somewhere around his right shoulder, hoping to allay the tension building between them. It was futile, however- she could still feel him looking at her, she could feel heat travelling over her as his eyes did. Her fingers gripped the stool as she felt the heat travel down her chest, beneath her dress…

Swallowing hard, she glanced around, making sure that nobody else was aware of what was silently passing between them.

Suddenly feeling bold, she looked up at him again, eyes twinkling. "Your tie's crooked."

Matthew's expression hardened as he tried to suppress the inappropriate feelings bursting through him. He was immediately transported back to last Wednesday, to his hotel room and his complaints about his tie that had sparked the most passionate night of his life. He remembered the way her fingers had curled around the knot to loosen it, touching him but not touching him, a slight smile playing on her lips.

He saw that she wore a similar smile now, although more knowing.

"You said that on purpose." It wasn't an accusation- he was stating a fact. The desire inside him grew more intense as he realised that she'd wanted him to remember that night, to remember what they did.

"Of course I said it on purpose. I didn't think you'd want to look sloppy amongst everybody else here." Mary said matter-of-factly, but the spark in her eyes betrayed her.

Matthew didn't reply- he wasn't interested in this torturous banter anymore. Not when he could practically feel her neck under his lips, feel her skin under his fingers as he slipped his hands under her clothes…

"Have you been here before?" He asked abruptly, determinedly.

Mary was momentarily taken aback. "Erm, yes, once or twice. We hired out this wing for a conference a few months ago."

"Was there security?"

"What?" Mary was perplexed at this line of questioning.

"Around this wing- were there any staff or security patrolling?" Matthew's voice was low but urgent.

"Places like this don't tend to have men with guns roaming around, Matthew." Mary said drolly. "Why?"

Matthew didn't respond. He placed his empty champagne flute on the nearby table and reached into his pocket, pulling out an iPhone and switching it on. "Keep your phone on." He said as he strode away, out of the room.

Go out of the door next to the painting of the woman with the green eyes, turn left and walk down until you get to the fifth door on the right.

It had been ten minutes since Matthew left the room when Mary received this text. In that time she'd been roped into a conversation with a television producer and the fashion editor of Harper's Bazaar, concocting vile plans for a new reality show. Making her excuses, she slipped out of the required exit as discreetly as possible, checking that there were indeed no staff loitering around as she hurriedly followed the directions.

She knocked once on the small oak door. It opened to reveal a very dimly-lit room, with Matthew pulling her in.

She found herself pressed up against the door as it closed, Matthew's strong body keeping her firmly in place as his lips captured hers. She immediately opened her mouth to him, moaning as he alternated between biting and nibbling and kissing and sucking. Her arms were around his neck, his hair bunched into her fists.

"Matthew." She whimpered as his mouth placed wet kisses down her neck and shoulder, his nose nudging the strap of her gown away so that it fell down her arm, just as he'd imagined. "Is this why you brought me here?"

Matthew ceased his attentions to look up at her, and she took the opportunity to cradle his beautiful face in her hands, appreciating how soft his cleanly-shaven jaw was. "You thought I'd brought you here to talk some more?" Matthew asked incredulously, and she smiled sweetly at the way his brow furrowed in disbelief, at how he thought it was obvious that all he wanted to do was kiss her, at how he looked at her adoringly even when he thought she was being stupid.

Mary reached forward to kiss him again, her hands running down his neck until they settled on his tie, trying to focus on loosening it as she revelled in the feel of Matthew's tongue on hers and his hands massaging the exposed area of her back. This was all the encouragement Matthew needed- he walked backwards towards the plush sofa in the middle of the room, wondering at how somebody could fit so perfectly in his arms, as Mary marvelled at how a man could make her feel so safe.

They made their way to the couch, as one, their subconscious minds desperately trying to capture every moment, every movement. Shedding their clothes as hastily as they could without causing damage. Laying down together, having to feel their way because their eyes were closed as they both lost themselves in their kiss. Feeling and touching and stroking, memorising each other's bodies. Breaking apart so they could see each other as they connected. Moving together, cursing and clutching and panting as they sought some way to release the unprecedented passion within them. Encouraging and quickening, wanting to bring each other to climax more than themselves. Savouring each other's sighs and moans, the way Mary's back arched and pressed her body into his, how Matthew's hands were so gentle yet scorched the skin they touched. How fierce and powerful those moments of bliss were as they peaked.

Mary allowed Matthew, and herself, a few minutes to relax before gently tugging his head up by his hair. She already missed admiring his handsomeness. Matthew took in her appearance, rosy and beautiful, and leaned down to kiss her lips. Mary felt like she could cry with happiness.

"Matthew, I-" She began too hastily, without thinking. It wasn't right to say those words. She stopped herself, her eyes dropping downwards as she distractedly ran her finger along the small shaving cuts on his neck.

Matthew's heart clenched as he watched her, her unsaid words more potent than any words he ever did hear. He kissed the tip of her nose tenderly. "Mary, I do too." He smiled as her eyes darted up to meet his in surprise.

Mary caressed his jaw and chin with her left hand, and Matthew dipped his head so he could kiss it, each finger reminding him of a moment they'd shared. He kissed the pad of her thumb, which had stroked his cheek as they'd kissed; her index finger, which had guided his own in between her legs, nine nights ago; her middle finger, which had dug into his back as they'd climaxed, leaving the greatest scar of all; her fourth finger, which…had two rings on it.

Matthew paused and looked up at Mary. Her eyes were wet, but she didn't let any tears fall. Neither of them said anything aloud- as was so often the case with them, they didn't need words to convey their meaning, everything was said through looks alone. If only we'd met sooner. If only I hadn't married the wrong person. If only we were allowed to be in love.

A/N: I realise the whole 'affair' thing is a bit controversial, but I hope it came across that they're not just having a bit of fun on the side. Please review, as I'm genuinely unsure what I think about this! xx