When I got home I parked the car and sat looking at myself in the mirror for a moment, my heart still seeming to skip a beat when I thought of Ben.

The house was quiet as I let myself in and then Rob and the children leapt out of the kitchen, yelling “Surprise!” , with the kids waving streamers and Rob brandishing a bottle of champagne. “To my beautiful wife,” he said, passing me a glass and pouring the bubbly almost in one movement.

“What did Mum do?” asked my little boy excitedly and Rob laughed. “Well, she’s top of the class,” he said, hugging me tightly as the children danced around us, and we all collapsed in a pile on the rug.

“You won’t believe who’s on the account with me,” I said casually to Rob “Your friend Ben.” He beamed at me in response.“That’s brilliant,” he said “He’s a lovely bloke and you’ll get on really well with him. Let’s get them over next weekend.”

Sitting around the barbecue a week later, I congratulated myself silently on having avoided being alone with Ben throughout all the consultations our firms had organised.

I knew that even contemplating being unfaithful to Rob was a betrayal in itself and I was determined not to allow myself to be tempted again, but I could feel my resolve giving way as Ben picked up a plate of food and grinned lazily at me.

“Clever, beautiful and a brilliant cook,” he said to Rob “Just what did we do in a past life to deserve such perfect wives?” Kelly laughed and ruffled his hair “Stop sucking up to Carol,” she teased “You’ve already got the job so you don’t have to impress anyone. But seriously, Carol, all I’ve heard all week is how great you are to work with – I can’t believe how well it’s all turned out.”

I looked at her for a moment as she leaned back comfortably against Ben’s arm and the wave of jealousy I felt almost stopped me speaking. “Well, the feeling’s entirely mutual,” I said eventually “I hope you and Rob don’t mind being deserted because Ben and I will be joined at the hip for the next few months.” As Ben looked quickly at me I knew he’d got the message, but I also knew that I would have to spell it out for him on Monday.

We were sitting in my office putting together a report of the initial work and as I passed him a folder of notes I caught his eye. “This sounds incredibly blunt but you need to know that I’m happily married and aim to stay that way,” I said quietly and there was a long moment of silence while I wondered if I was making a total fool of myself.

“ I know,” he said “I feel exactly the same way about Kelly and the kids but I’m mad about you. What harm could we do if no-one knows?”

Rob’s handsome face crossed my mind for a moment but I pushed that thought away. I wanted Ben and if no-one knew, then no-one could get hurt.

“Ok, but we stick to the ground rules. No texts, emails, messages – no trail to get us into trouble. We’re friends, we work together, we have every reason to see each other but no matter what happens, we deny everything.” I said vehemently and Ben looked slightly taken aback, but nodded quickly.

“Our company has an apartment we use for entertaining or visiting staff,” he said “ I look after it and I’m heading there this afternoon. Would you like to join me?”

That was nearly two years ago and we’re still seeing each other at least twice a week. Most people have affairs as a way out and so have an end in sight, but I want to stay married to my lovely Rob and keep my lover too, and so far we’ve done a great balancing act.

Both families still socialise together and Ben and I see each other for work, but we also have an extra secret life which gives us great pleasure and doesn’t concern anyone else.

Sometimes I’ll say to Rob that I saw Ben at a conference and we had lunch or coffee together, but of course I don’t mention the two hours we spent in bed first. There’s no need for that ever to change and I’m sure many people would criticise us fiercely, but be honest – if you could have an affair without any chance of being found out, wouldn’t you be tempted?

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