THE SEX COLUMN: My X-rated fantasy became reality when I told my lover I only wanted his young hard body for one thing…

Female fantasies are once again a topic of conversation among my girlfriends, thanks to Want, the new collection of anonymous essays edited by Gillian Anderson. I was fascinated – and relieved – to read that other women feel ashamed of what they think when they have sex, or when they’re alone. I felt that way too, for years.

I worry that my fantasies are weird, or too intense, or anti-feminist, or that they negatively impact the sex I actually have.

Unfortunately, as my (now ended) marriage progressed, the role of fantasy became more important, for both of us. It was easy to pinpoint Simon’s sexual fantasy: he liked to imagine another man in bed with us.

I later read that this scenario is very common, especially among married couples. Still, I was surprised at the time.

The reality was that I was the “good” wife and mother of our three children; the fantasy was that I was the “bad” girl, having sex with him and another man at the same time. Classic Madonna/Whore complex.

It goes without saying that this fantasy never became reality.

But my fantasies were harder to talk about. I’m inclined to say my biggest fantasy was Simon taking the bins out without complaint, or arranging the children’s haircuts. The long hours I spent watching Emi’s favourite BBC show, Operation Ouch!, were enlivened by the enormous crush I had on both presenters, the Van Tulleken twins, in their colourful scrubs. They could examine me at any moment.

But the truth was that the more I got caught up in domesticity, the more outrageous my fantasies became. And by the end of the relationship, it seemed easier to get lost in the fantasy in my head than to be present with Simon. It left me feeling lonely – and guilty. I had barely been in the room.

With Eliot, I didn’t have to fantasize at all at first – he was the dream. But around the eight-month mark of our relationship, I found myself reaching for my favorite X-rated scenarios, only now it’s different: instead of the usual secret dirty movies playing in my head, I was still there. We were both still in bed, having sex, only sometimes I gave our situation a little more depth.

When we watched Braveheart last month in his North London apartment, I felt like I was in 13th century Scotland.

Instead of dropping his jeans, Eliot had simply unbuttoned his kilt (which he would have looked great in). Instead of the slightly uncomfortable bed in his small rented room, we were in an even more uncomfortable hut surrounded by ferns. His body wasn’t far off from that of a young Mel Gibson, so it wasn’t much of a challenge.

Sometimes I imagined we were being watched. Objectifying what the real us was doing made it even hotter. Still, I kept these things to myself: I wasn’t sure how Eliot felt about playing William Wallace, and I knew he wasn’t into voyeurism.

But last week, while his roommates were away and the kids were in school, we met up for an afternoon of naughty sex.

I loved Eliot for many reasons, he was funny, caring, successful, but he was also young and fit. And I knew that I was the sexy older woman to him. It struck me: our age difference was our ultimate sexual fantasy. We lived it anyway, but it would be even hotter if we were open about it.

I leaned back and guided his hand to my breast, then pushed his hand further down. Then I took the risk – and spoke. ‘I’m only here for one thing,’ I told him (not entirely true, we’d shared a sandwich earlier), ‘and you’re going to give it to me, with your young, hard body.’

Eliot looked at me, his eyebrows raised, but I persisted. ‘First you do anything I want to me, like a good boy,’ I told him. ‘And then, if you’re really good, I’ll let you do whatever you want, which is…’ I listed a few things, explicitly.

Eliot gasped. “Tell me again,” he said.

I told him again, but made it even dirtier.

“Yes, yes please.”

It was actually a role-playing game, but only because we talked ourselves into the roles.

There was also a bit of fantasy in my head, that I would use Eliot mercilessly and then get up and leave, no strings attached. But really, when I left to do the school run, my heart ached for days.

• Annabel Bond is a pseudonym. Names have been changed