The night was hot and sticky as I tossed the duvet aside, twisting and turning as I attempted to get some sleep.

Next to me Matt*, my partner of five years, lay dead to the world and I envied his ability to sleep whatever the temperature.

But no sooner had I finally nodded off than I was woken up by Matt climbing on top of me, pushing my legs apart with his knees.

It took me a moment to register what was going on.

But no, this wasn’t some bizarre dream, my boyfriend really did seem to be trying to have sex with me, a familiar glazed look in his eyes.

I couldn’t think of anything I wanted less at the time and, thankfully, once I’d shouted his name and shaken him, he collapsed on top of me, snoring softly.

After rolling him back onto his side of the bed, I managed to catch a few, uninterrupted, hours of sleep before my alarm went off.

My reaction might seem surprisingly calm given my boyfriend’s behaviour – not to mention the fact this wasn’t the first time it had happened.

But it was because I’d experienced this aggressive nocturnal sexual attention before that I knew not to panic.

Because Matt’s eyes were glazed not with lust, but with sleep.

Matt’s GP agrees that he shows all the signs of sexsomnia, a sleep disorder in which sufferers carry out sexual activity – whether it’s masturbating or even attempting to have intercourse – while they are fully asleep.

Sexsomnia is a type of parasomnia – an activity that happens during sleep – and it typically occurs because of a blurring between the conscious and unconscious part of the sleep cycle

A type of parasomnia – an activity or behaviour that happens during sleep – it typically occurs because of a blurring between the conscious and unconscious part of the sleep cycle. As in Matt’s case, sufferers have no recollection of their actions when they wake up the next day.

But while most of us have some experience of other parasomnias, such as sleepwalking and sleep talking, sexsomnia is much rarer – and more disturbing.

Until I started researching Matt’s increasingly troubling night-time behaviour, I had barely heard of the condition.

It’s estimated only one to two per cent of the population will experience it at some point in their lives and is reported to be more common in men.

But sexsomnia has received increasing publicity in recent years because of the rise in the number of men using it as a defence in rape cases.

Last year, an Australian man was cleared of having non-consensual sex with a woman after he claimed he’d suffered an episode.

Meanwhile, in 2024 a British woman successfully sued the CPS for £350,000 after her alleged rapist was acquitted before he was due to stand trial after two sleep experts claimed she could have been affected by sexsomnia. Offering her an apology, the CPS admitted that the case should not have been dropped.

The associations with sexual assault explains why Matt was horrified when I eventually told him what had been happening.

I, too, have been afraid to share my experiences with even my closest friends in case people judge him negatively.

While some may suspect that he’s just been trying it on with me at night, I truly believe that he has no idea of what he’s doing.

Ironically, it was only after I confided in him about what he’d been doing that our relationship came close to breaking point, more than it ever had been when he’d been trying to molest me in his sleep.

Both in our early thirties and working in finance, we got together five years ago after meeting through mutual friends at a birthday party.

With similar libidos, we enjoyed an enthusiastic sex life and would fall asleep in each other’s arms with no issues.

Then, two years ago, we made the decision to move in together. It was just a couple of months after setting up a home that Matt’s nocturnal habits began to change.

Initially, it was a wandering hand cupping my breast or a rogue erection I could feel when he spooned me, and was happening a couple of times a month.

While it woke me up, I took it as a compliment – he even fancied me when he was asleep!

So when it started happening more frequently I was smug, not concerned.

But as time went on, the erections started to be accompanied with a thrusting motion and increased to at least twice a week.

I’d elbow him in the ribs and try to turn him over, all of which he snored his way through.

But because I was so startled, having been woken around 2am, I’d not get back to sleep until 4am.

Sleep-deprived, I became irritable and my coffee intake went through the roof.

And it wasn’t just the lack of sleep that was unsettling me.

While we were making love regularly – at least once a week – he seemed more turned on when he was unconscious than when he was awake.

I was unsettled enough that I mentioned the erections to him. Was he having dreams about another woman, I asked him nervously?

Matt told me most men have erections when they sleep, insisting there wasn’t anything else going on.

A quick Google search reassured me this is completely normal and caused by fluctuating hormone levels during REM (Rapid Eye Movement) sleep cycles.

But over the following six months the thrusting started to get more aggressive and Matt began clamping his leg over me as he did it, gripping on to my shoulders or waist as he attempted to climb on top of me. My elbowing turned to hard shoving to get him off.

He also graduated to trying to take off my pyjamas and attempting to force his hand between my legs, all of which I fended off.

I was getting more concerned but didn’t say anything, not wanting to embarrass him or throw a spanner in the works at a time when he and I were both already stressed at work.

I realise why some women might be terrified, but I was never scared.

Matt has never laid a hand on me in a violent or threatening way, and it never occurred to me that he would. Every time, I was able to push him off easily.

It was, however, disturbing – and very, very annoying.

Sexsomnia presents a challenge because, while it was officially recognised in the International Classification of Sleep Disorders in 2005, there is no standardised way to diagnose it

While not tackling the subject directly, I started asking pointed questions the morning after an ‘event’, such as ‘Did you have any weird dreams last night?’ and ‘How did you sleep?’

Bemused, he usually said he’d slept fine.

But I started to get snappy with him because I was so tired.

Date nights ended in bickering and little things around the house sent me into a rage: shoes in a heap at the door, washing up left to fester.

I felt like I was living with someone I didn’t fully know and had no idea how to approach it. Not to mention the sense that I was keeping something from him, which I also found distressing.

And throughout it all, at the back of my mind I was worried it was all because there was someone he fancied more than me who was inspiring his night-time lust.

Our waking love life began to suffer too, taking a hit from my lack of sleep and fears that Matt wasn’t attracted to me.

Several months passed like this and then, right before we were due to go on holiday, his middle of the night activities seemed to subside.

We went away, where we both slept like babies, and I hoped Matt’s bizarre behaviours had stopped. Perhaps the cause had been stress at work? He had recently been promoted, so that would make sense.

But once we returned home his pestering only ratcheted up again.

It wasn’t always unwelcome.

One evening after a romantic date night, which had included a few too many cocktails, we wobbled home and collapsed into bed.

Too tired and tipsy for sex we kissed and fell asleep immediately.

But in the early hours of the morning I awoke to find him pushing himself into my back.

On this occasion I confess I was turned on by it.

He then turned me over and started undressing us both and we made love.

Though he seemed to be responding as normal, looking back the signs were there – he didn’t say anything to me, whereas usually there’d be sounds of appreciation or encouragement, and his eyes were glazed over.

He didn’t finish, which I attributed to the cocktails, and was snoring again almost instantly afterwards, which left me miffed. I’d at least expected a cuddle.

The next morning, when I told him I’d been surprised, if not entirely unappreciative, at our night-time liaison, he had no recollection of it.

The mood turned sour immediately. I was upset he hadn’t realised, or even been mentally involved and also felt uncomfortable, as though I’d exploited him.

I felt horribly conflicted; he hadn’t remembered it, but at the same time his body had reacted as if he had known what he was doing.

I began to withdraw from Matt, no longer snuggling up on the sofa or offering more than a peck on the lips because I felt uncomfortable and confused around him.

While he didn’t comment on it, he seemed sadder too and didn’t try to instigate intimacy, so I wonder if he felt similarly conflicted about what had happened.

Then, almost six weeks later, I woke up to a strange sound.

Frightened, I sat up to listen and realised the sound was from in the room.

Matt was curled up next to me, facing away, and as I went to put my hand on his shoulder to wake him up I realised he was masturbating aggressively but appeared to be completely asleep.

Then he stopped, rolled on to his back and let out a huge snore.

I was so shocked; it no longer felt like it could be explained away as a physical reaction to a saucy dream or even an attraction to me.

It was unnerving to see him doing that while looking totally asleep.

Afterwards, I stayed awake for hours researching what I’d seen.

It was the first time I came across the term sexsomnia, including in news articles about rape cases and Reddit threads of first-hand accounts.

I felt we’d reached the point where I had to tell Matt what had been going on. As soon as he woke up the next morning, I laid out the details of the past 18 months.

He was utterly mortified and quite distressed.

Apart from me telling him about the night-time erections, he had no idea anything had been happening.

Matt told me tearily that it made him feel ‘rapey’ and like ‘a freak’. He hated the idea that he had no idea what he was doing in his sleep.

I asked whether, to his knowledge, this had happened before, and he said no. No previous girlfriends had ever mentioned anything.

He peppered me with questions: Had he ever hurt me? Did he say anything while he was doing it?

Sexsomnia has received increasing publicity in recent years because of the rise in the number of men using it as a defence in rape cases

And then, most heartbreakingly, did I still want to be with him?

To which I responded with a heartfelt ‘yes’, adding that I was sure there were things that could be done to help.

Part of Matt’s horror was because the only time he had ever heard of the term was during a high-profile rape case last August, in which violent thug Dean Final claimed to suffer from sexsomnia in a bid to walk free after raping two women.

While Final, 32, was nonetheless convicted, the connection did little to soothe Matt, who for the next few weeks would wake up every morning with a worried look on his face, asking me if he’d touched me in his sleep again.

I was heartbroken seeing him so anxious and on the mornings I confirmed that he hadn’t he would breathe a sigh of relief.

But the fear that he might do something was clearly affecting him profoundly and he began to withdraw from sex altogether.

The result was that I felt rejected and unattractive, while my loving boyfriend felt awkward, and we started bickering.

Without any intimacy I was worried we wouldn’t last.

We had a frank conversation about the state of our love life on the sofa one evening and I explained I couldn’t carry on like this – that I was worried we were breaking up and that I regretted ever telling him about his night-time activities.

Matt said he felt tainted and was worried that if we had sex he might then do something extreme or violent later that night.

It wasn’t until a weekend away in Cornwall recently after a few drinks, giddy and sunburnt, that Matt felt confident enough to vanquish that particular bogeyman.

Matt has since been to see the GP and he’s now waiting for a referral to a sleep specialist.

Sexsomnia presents a challenge because, while it was officially recognised in the International Classification of Sleep Disorders in 2005, there is no standardised way to diagnose it.

Diagnosis usually involves a sleep study where the patient stays overnight and their brain waves, heart rate, breathing, oxygen levels and movements are all monitored. Accounts from partners are also taken into account.

However, sleep expert Dr Oliver Bernath – who sees sexsomnia cases in both men and women at his sleep disorders centre at Queen Victoria Hospital in West Sussex – told me it can still be difficult to establish what’s really going on.

‘This ambivalence adds to the strain this condition typically places on a couple,’ he says.

‘These conditions are medically benign - not associated with any brain disease - but the behaviours can be problematic.

‘The impact of this condition on couples who share a bed can be anything from annoyance, to feeling forced to sleep separately, even to rape allegations.’

He also says that, despite what I’d feared about what might be going on in Matt’s dreams, this activity is typically not associated with dreams of a sexual nature. Instead, it happens during a partial awakening from so-called Non-Rapid Eye Movement (NREM) sleep, as opposed to the deeper REM sleep in which we dream.

I don’t know yet if there’s a ‘cure’ or if this is something Matt will have for the rest of his life.

Dr Bernath says the behaviour can be triggered by lifestyle factors including drinking too much, stress and a lack of sleep but that no definitive cause has been found, and it’s unclear why it affects some people and not others. Interestingly, there’s no known link to hormone levels or libido.

For most it’s episodic and can be managed with a healthy sleep routine, including no screens before lights out and a regular bedtime.

Dr Bernath says treatment also involves relaxation techniques, and beyond that medications such as anti-depressants can help.

Matt is now trying his hardest to drink less and have a healthy bedtime routine.

Now, instead of being woken up a couple of times a week, it’s once every few months and I’m open to him about it the next morning when it happens. He is less anxious about it too.

Perhaps most importantly, our waking sex life – and our relationship – is back on track.

• Jodie Garraway is a pseudonym. Names and identifying details have been changed.