Kevin slammed down his glass in anger. He knew it had been a mistake to come to the reception, and Arabella’s behaviour was already proving him right. He looked across the room to where she was standing much too close to Dave Costello, her wine glass at a tipsy angle, giggling at some inane remark he’d just made. He saw Dave glance down at Arabella’s ample chest, her embonpoint almost spilling out of her low-cut black cocktail dress. On some women it would have looked elegant, but Arabella managed effortlessly to make it appear slutty. Kevin acknowledged grimly the implications of this observation. It wasn’t the dress that was slutty, it was his wife. He remembered her comment when he’d suggested she should wear a bra underneath: accusing him of being a prude, and that underwear of any sort just spoilt the “line” of the dress. He knew she just wanted men to look at her boobs, and if there was an opportunity to reveal her lack of panties as well, that would be even better.

“Don’t you want me to look attractive for our friends?” she had asked rhetorically. Kevin had been tempted to point out that (a) he didn’t know most of her work colleagues; (b) the ones he did know seemed to be arrogant arseholes; and (c) there was more to looking attractive than flashing your knockers all over the place. But he’d wisely held his tongue.

Dave Costello would presumably have disagreed with point (c). While still gazing at Arabella’s boobs, he casually swiped two full wine glasses from the tray held by a passing waitress and gave one of them to Arabella, who simpered even more at his “gallantry”, as she’d have described it. Dave lent over and whispered something in her ear, and Kevin spotted her glancing over in his direction while she sipped from her glass. Was that a slight blush on her cheek, or just the effect of the wine? He wasn’t sure, but he did know that embarrassment wasn’t really in Arabella’s repertoire.

Kevin took another swig from his own wine glass. He decided he might as well get drunk, since they’d be getting a taxi home anyway. Arabella would be pissed too, and he just hoped she wouldn’t throw up all over the taxi’s upholstery, like last time. That had cost him an extra hundred quid on top of the usual fare.

This thought had distracted him for a moment, and when he looked over towards Arabella, she’d disappeared. Dave Costello wasn’t in sight either. Kevin scanned the room, and caught a glimpse of Arabella’s back disappearing through the door. And what was more, Dave was there, his hand firmly placed on her trim bottom. Kevin sighed. No doubt they’d be finding a quiet spot somewhere for a quick snog, and Dave might even chance a quick grope of Arabella’s tits through her dress. Kevin didn’t suppose she’d object.

He looked round. There wasn’t even a fresh glass (or even a bottle) of wine when you wanted one. He decided to go for a pee first, and then seek out more alcohol to take his mind off the thought of Dave Costello tweaking his wife’s perky nipples. The bogs downstairs were occupied, so he wandered upstairs to where he had a vague recollection there was another set. Luckily these ones were free, so he stood and emptied his bladder while wondering how long he dared leave it before suggesting to Arabella that it was time to go home.

His mind elsewhere, he took a wrong turn out of the toilet and found himself in a part of the building he didn’t recognise. Turning round to retrace his steps, he was suddenly distracted by a giggle, and a muffled exclamation that sounded like, “No, I can’t.” It seemed to be coming from one of the adjacent offices. He looked up to try and identify the precise source, and noticed that the door to one of the rooms wasn’t quite shut. His curiosity got the better of him, and he quietly positioned himself by the door and put his eye to the gap.

His heart missed a beat as he saw Arabella and Dave Costello leaning against a large desk. Dave’s trousers were down round his knees, and his erect penis was sticking out of the front of his boxer shorts. Arabella was holding it in her hand, stroking it gently, and Kevin was horrified to see that her dress had been pulled right down and Dave was kneading one of her bare breasts.

“Suck it, babe,” muttered Dave Costello, and Arabella looked at him with a filthy grin. Without a word, she knelt down and pulled on his foreskin, revealing his shiny knob-end, then stuck out her tongue and licked gently round the tip.

“Oh fuck,” gasped Dave Costello, his penis twitching at the sensation. Kevin knew what he was feeling. It was a long time since Arabella had fellated him, but she was a real pro, seeming to know exactly when to lick, when to suck gently, and when to go at it 100%, like a Dyson turned up to 11.

She also knew how to deep-throat, and Kevin watched as the whole length of Dave’s erection (a good eight-inches worth) disappeared slowly down her throat, before emerging a few moments later coated in Arabella’s saliva. Dave had begun to play with her breasts again, and Kevin could see how hard and aroused her nipples were.

Some husbands, on catching their wife in the act of giving head to another man, would have burst in and beaten one or both of the guilty parties over the head with a convenient item of office furniture, like a telephone or a chair. But something stopped Kevin. This was partly because he knew that in any encounter of that sort he would be bound to come off worst, but also because (to his surprise) he was beginning to feel more than a little aroused. He could feel his own penis stirring into life in his trousers, blood surging into it as he watched his wife’s lips wrapped around another man’s erection.

Glancing quickly around to make sure he wasn’t being watched himself, he slid down his zipper, put his hand in, and eased out his tumescent organ. It was surprisingly hot, and in a few seconds it had swelled to a hardness he hadn’t experienced for a long time. Cradling it in his hand, he noticed that the shiny helmet was already sticky with secretions of pre-cum liquid. It throbbed excitedly as he squeezed it, rubbing his thumb against the sensitive edge of the helmet.

Looking back through the door, he was just in time to see Arabella withdraw Dave Costello’s penis from her mouth. Her bright red lipstick was smeared over the sides of her mouth, and some of it had rubbed off onto Dave’s shaft.

“Fuck me,” she said; and it wasn’t an expression of surprise. It was an order. Just two words that made Kevin’s heart stop and his penis tingle. He wouldn’t, would he?

Dave Costello didn’t pause to ask stupid questions. He just grunted and turned Arabella round, roughly bending her over the desk so her big breasts dangled and her bum stuck up in the air. He pushed her dress up around her waist, exposing her knicker-less bottom, and eased her cheeks apart with one hand while grasping his erect penis in the other.

Kevin just caught a glimpse of the pink folds of his wife’s vulva, looking very wet and aroused, as Dave positioned his penis at the entrance. Kevin’s own cock was almost painfully erect, and he rubbed it slowly as he watched Dave Costello’s hard-on disappear into his wife’s vagina. Judging that no-one in the room was likely to be looking in his direction, he eased the door open a little, giving himself a better view.

He watched as Dave Costello put his hands on Arabella’s hips and began to pump his cock in and out of her hole. Kevin could hear the schlup, schlup, schlup of her copious juices, and she began to let out a sequence of squeaks and gasps as she sprawled over the desk.

“Oh Dave, yes Dave,” she squealed, “Oh fuck yes, oh fuck, that’s it.”

Kevin began to masturbate in earnest. Suddenly he had an idea, and pulled out his phone. Activating the movie camera app, he aimed it through the gap in the door with one hand while continuing to pump his penis with the other. He had a feeling he’d enjoy watching it back, and masturbating all over again.

Dave Costello didn’t actually last very long before he began to speed up.

“I’m gonna come, babe,” he announced, his pale buttocks tensing up.

“Oh shit, pull out, don’t come in me!” squealed Arabella, and Kevin watched as Dave Costello withdrew his penis with a final schlup and launched several large ropes of semen all over her back. At the same moment, Kevin gave his own cock a final rub and ejaculated all over the door, even more copiously than Dave. He looked at the thick gloops of creamy semen as they began to ooze slowly down the paintwork. He paused the camera app on his phone, then quickly found his handkerchief and wiped the door clean as best he could.

Meanwhile, Arabella was scolding Dave Costello as she adjusted her dress and eased her boobs back into place.

“Oh shit, Dave, look, you’ve got cum up the back of my dress, you arsehole,” she complained, looking over her shoulder and trying to dab it off with a tissue.

“Well, you told me to pull out,” Dave retorted, pulling up his trousers and tucking his penis away. “If you’d let me come inside, it’d be fine.”

“No it wouldn’t, you wanker. I’ve got no knickers. It’d’ve be running out all down my legs before I’d got home.”

Dave didn’t seem too concerned.

“Come on babe,” he complained, “Let’s get back downstairs before your old man comes looking for you.”

“He won’t have noticed I’m gone,” said Arabella, inaccurately.

Kevin quickly slipped away, and had managed to find himself a seat in the corner before Arabella came looking for him. When he saw her looking round the room, he shut his eyes and pretended to be asleep. Stalking over, she shook his shoulder, and he did a good imitation of someone coming round after a nap.

“Oh, hello love,” he said. “You want another drink?”

“No, come on, let’s go,” she said, “I’m bored, and you’re embarrassing me, lying there like that. Let’s get moving.”

He called a taxi, and had another drink while they waited. Arabella seemed distracted (as well she might) and was snappy in the cab all the way home. Maybe it was that, combined with the drink, but Kevin was quite angry by the time they reached their destination. He paid off the driver and followed her up the path to their front door. Going into the front room, he dropped his jacket onto the sofa and poured himself a large Laphroaig.

“For Christ’s sake, haven’t you had enough?” Arabella snapped.

She bent down to pick up her bag, and Kevin could see the marks of Dave Costello’s semen smeared all over the back of her dress, which she hadn’t made much of a job of cleaning off.

“What’s that up your dress?” he said. “It looks like mayonnaise. Did you have a food fight back there with what’s-his-name, Costello?”

“Dave, his name’s Dave,” said Arabella sharply, spinning round so he couldn’t see the stains any more. She fiddled with her bracelet, a sure sign that she was rattled for once. “You know I need to butter him up. He could really help me get the best contracts at work if I keep on the right side of him.”

“Maybe it’s butter then,” said Kevin incoherently. “A knob. Of butter.”

“What the fuck are you going on about? What knob? Come on, explain.”

It was probably the whisky that did it, but instead of shutting up, Kevin just blurted it out.

“Oh come on, Arabella, you know all about knobs. I know what you were doing. Fucking Costello. Up there in that office.”

“What? How dare you! Of course I wasn’t. You take that back, you bastard.” She was taking off her shoes, and for a moment Kevin was worried by the way she was wielding the stiletto heel.

“So what’s this then?” he said, taking out his phone. He found the snatch of film he’d taken that evening, and held it up for her to see.

Livid with anger, she snatched it out of his hand and looked the small screen, watching as Dave Costello rammed his thick cock in and out of her.

“You were watching, you fucking cunt. You pervy fucking cunt,” she spat out. “How dare you…”

Then she paused, and to his surprise began to laugh loudly.

“And you were wanking, you were jerking off!” she cackled.

It was Kevin’s turned to be surprised.

“What? I wasn’t…” he stammered, instinctively going into denial mode.

Arabella held out the phone. “So whose dick is that then?” she asked. Kevin looked at the screen and realised with horror that his hand holding the phone had clearly slipped at the climactic moment, and his own hard penis filled the screen. Arabella had paused the movie precisely at the point of ejaculation, and they both looked at the blurred shot of his thick semen shooting out of the end.

“You were turned on,” said Arabella gleefully. “You were watching us fucking and it turned you on. You got your cock out and you wanked yourself off, didn’t you?”

She looked at him, and Kevin was surprised to see a strange look on her face. It wasn’t shame, or anger. It was excitement, maybe even desire.

“Fuck it, Kevin, is that it? Is that what made you hard, watching me get fucked? Watching another man’s cock in my cunt? Watching him come all over my back? And you came yourself?”

She licked her lips.

“Fuck, that’s hot. If I’d known you were watching…”

She came up to him.

“I always thought you were so boring in bed. Just fucking me and going to sleep. When all you really wanted to do was watch me get fucked.”

She looked down at his crotch.

“Jesus, you’re turned on now, just thinking about it, aren’t you?”

She was right. Kevin could see his penis straining at his trousers, erect again.

“God, I wish I’d known,” she repeated. “You standing there with your dick in your hand, jerking…”

She put her hand on his crotch and rubbed it. Kevin breathed in sharply at her touch, and suddenly she began to drag down his fly. In the same instant, he fell on her, kissing her red lips, dragging at the straps on her dress, pulling them down, feeling her bare breasts hot in his hand. Her nipples were rock hard, and as she grabbed his cock he bent over and took one in his mouth, biting at it roughly, in a way he’d never done before.

They were ripping at each other’s clothes, falling naked onto the carpet. There wasn’t any need for foreplay: or perhaps the whole evening had been the foreplay. Arabella opened her legs wide, her pussy wet and inviting, and without further ado Kevin shoved his hard cock straight into her. She wrapped her legs around him, pulling him closer and biting at his shoulder, so hard that she drew blood. He rolled her over, and took her roughly from behind like Dave Costello had done, his balls slapping against her thighs. He could see her rubbing at her clitoris as he banged away, her squeals and gasps arousing him even more.

The cheeks of her bottom wobbled with each thrust. On an impulse, he withdrew his cock, slick with Arabella’s cunt juices, and pressed it against the dark pucker of her anus.

“No, not there,” gasped Arabella, but Kevin took no notice. Never before had he even contemplated taking his wife up the arse, but now the thought of it almost made him come on the spot, and he lunged forward, his cock burying itself deep in her back passage. Arabella shrieked and her sphincter contracted, clutching him tight, but he slowly withdrew before thrusting back, discovering for the first time the pleasure of fucking a really tight arsehole.

“Ah, fuck my arse Dave, fuck my arse,” she gasped.

Kevin smiled wryly. Putting on his best Dave Costello voice, he leant over and whispered in her ear.

“He’s watching us right now, your husband. He’s watching me fuck his slut of a wife up the arse. And he’s got his prick in his hands, he’s wanking, he’s watching me come right up your tight arsehole, you slut.”

“Come in me, Dave,” whimpered his wife, “Now. Let him see you come in me.”

Kevin felt his climax approaching, his semen boiling up inside his balls, and he gripped Arabella tight as it gushed up his cock. With a groan he ejaculated deep into her backside, holding himself inside her until he felt the final throb of his ejaculation, squeezing out the last drop of semen. Slowly he pulled out, his cock slick with his own ejaculate, and watched as Arabella lay still, gasping as she squeezed out dollop after dollop of his semen, letting it run down between her cheeks onto the carpet.

With a sigh she rolled over, putting her hand between her cheeks and gathering up a sticky helping of his cum. She put her fingers in her mouth and sucked it off.

“Why didn’t you ever come in my bum before?” she asked with a filthy grin. Kevin blushed, not wanting to admit his innocence of anal sex. Arabella put her arms around his neck and kissed him. He could taste his own semen in her mouth, and he felt his cock stirring again. Somehow, he knew that their relationship was entering a whole new and challenging phase, but that whatever happened, one thing was certain. Nothing would ever be quite the same again.