When the menopause knocks at the door, sex flies out of the window. As bedfellows go, there couldn't be a less compatible pair.
Thanks to plummeting hormones, a woman's libido goes into free fall, often never to be revived. The only thing you desire right now is a good night's sleep and an open window.
That, at least, is the accepted wisdom.
We've been told this so often that to even hint, well, that it's not quite how many women experience it, is to mark one out as something of a traitor.
In the arcane world of menopause show and tell, if you can't make jokes about your appalling sex life and how you hate the very idea of making love, you're just not one of the club of suffering sisters.
It may have come as a surprise to some, therefore - though not especially to me - when in July former tennis champion Chris Evert, now 61, blamed the menopause for the affair which ended her 18-year marriage. Not her husband's affair. Hers.
"We had a rough couple of years," said Evert of her marriage to American Olympic skier Andy Mill, father of her three sons.
"I was going through menopausal stuff that doesn't get talked about enough - what women go through, you know, at 50ish."
Whatever she was "going through" in 2006, it led to an affair with her husband's friend, golfer Greg Norman, whom she subsequently married. It lasted 15 months and broke a lot of hearts.
It would be easy to dismiss Evert as just another attractive, successful woman, panicking about ageing and attempting to justify her uncharacteristic, destructive behaviour on her hormones, rather than being accountable for them.
The hidden side of menopause
While I cannot condone her actions, I can certainly understand the sentiments behind them.
For the hidden side of "menopausal stuff" - suddenly feeling attractive again, having erotic dreams, even thinking about sacrificing middle-aged comfort and family stability for the frisson of illicit sex - is seldom addressed at all.
The reason I'm not surprised by Evert's fling is because when my own relationship of 20 years was going through a fatally bad patch, eventually leading to separation and divorce, I was at around the same age and stage in life as she was.
I was in my early 50s and perimenopausal - my sex life had dwindled away almost completely - when suddenly I found myself harbouring fantasies of the kind of passionate affairs that would make me feel young, womanly and appreciated again.
Even at this age, and despite my dodgy hormones, I experienced feelings of desire. Although lacking an object for my affections - I felt emotionally and physically rejected by my husband - I could sense a spark of libido, waiting, longing to be ignited.
For me, though, the sex was all in the head, because I'm a useless liar, plotter and deceiver (all pre-requisites for a successful fling) and still unfashionably wedded to the idea of fidelity.
When I confided to a slightly younger perimenopausal friend she grinned at me slyly. "The only difference between you and me," she said, "is that I have the courage to go out and do something about it".
She went on to detail how her husband barely acknowledged her existence any more, except when he wanted sex. "My lover, on the other hand - how I love the sound of that - lavishes me with attention.
"Neither of us want to run off together, so perhaps it's a last hormonal hurrah. But whatever it is I don't intend to feel guilty about it."
Although she fully intended - and has succeeded - in staying with her husband, it can't be a coincidence that divorce rates among 50-year-olds are rising. While other age groups remain static, the "HRT splitters" have increased by more than a third in a decade.
Women of today
Also, it can be no coincidence that a 50-year-old woman today looks very different to one of a generation ago. She exercises, watches what she eats, and is, in some cases, in better shape than a 25-year-old.
Whereas in the past, opportunities to stray were few and far between - a lusty menopausal woman of our grandparents' generation may have consoled herself with a Mills & Boon novel - today there are many outlets for a late-life surge in libido.
Looking back more than a decade, the hormonal fluctuations in the run-up to my menopause, at a time when I no longer felt loved or desired, may well have contributed to my ramped-up sexual imagination.
When I met my current partner at the age of 56, a year after separation from my husband, I was at peak menopause. I was experiencing hot flushes, night sweats and sleeping appallingly. I was also having the best sex of my life. And I wasn't even taking HRT.
At the time, I put this down to the confidence boost of a new relationship. Now, I realise I may also have been experiencing what a growing body of medical opinion is calling a "late-life lust surge" - a sexual surge at the very moment when women are supposed to have lost all interest in sex.
My menopause, it turned out, was a transition - not a road block - in my love life.
This is thought to be influenced by testosterone, the male sex hormone that men have in abundance, but which also contributes to female libido.
During the perimenopause, the slow countdown to infertility which can begin up to a decade before your periods cease, oestrogen levels fluctuate and fall.
But there's a period in which testosterone remains relatively high. This is because, while testosterone peaks in your 20s, and then halves by the time you reach 40, the decline after that age is less dramatic.
At this point, when there are fewer hormone binding chemicals in the blood to dampen its effect, there's effectively a testosterone spike.
An upsurge in libido
Psychiatrist Dr Julie Holland, who has a special interest in the effects of hormones on our wellbeing and is author of Moody Bitches, which explores the relationship between the two, suggests there may be an upsurge in libido during this period.
Any drop in testosterone, whether it is produced in the ovaries or the adrenal glands, is age, rather than menopause, related.
"In early perimenopause, around the ages of 40 to 42, increased libido is very common," says Holland.
"It's also a common time to have affairs, which is where the notion of the Cougar came from. From then on, it's more of an individual thing.
"Providing you are still getting periods, even if they're irregular, you're guaranteed to get a mid-cycle spike in your libido. This can be the case well into your 50s."
Of course, it would be incorrect to suggest that women are entirely slaves to their hormones.
Claudine Domoney, a consultant gynaecologist at the Chelsea and Westminster Hospital and a member of The Institute of Psychosexual Medicine, says it would be misleading to focus on hormones to the exclusion of a woman's life and relationships.
"There are some women who feel better about sex when they no longer have to worry about contraception," she says.
"Perhaps they're more confident because they are taking HRT. Or because they're no longer so focused on being a good mother now the children have grown up."
When the kids leave home
I recall a former colleague who had three kids at a young age, the first when she got pregnant at 20 and dropped out of college. By her late 40s her kids had left home and her sex life suddenly took a turn for the better - the freedom to do it anywhere in the house, rather than silently behind closed doors, being one factor, as well as a certain sense of liberation from parental responsibility.
When she told me this 20 years ago, neither of us would have considered that a positive surge of hormones might have also had something to do with it.
On the other hand, says Claudine Domoney, "I have women who come to me and say, 'I feel desire with my lover but not my partner. Can you help me?'"
"I have to tell them there isn't a magic pill for this because sex is a mind/body activity. It's not separate, ever. Yes, HRT can bring back desire as symptoms improve, but it's an individual response."
As for post-menopausal sex, Domoney is keen to explode the myth that a diminishing sex life is mainly because women have lost interest.
"There is evidence," she says, "that ceasing to have a physical relationship after the menopause is more likely to be male than female driven.
"If the man develops sexual difficulties, the woman will excuse it with a loss of libido on her side which doesn't necessarily reflect how she really feels."
This is backed up research led by Dr Tim Spector, professor of genetic epidemiology at King's College London.
In studying women's responses to questions about desire, arousal, orgasm satisfaction and pain during sex over a four-year period both pre and post-menopause, researchers found the rate of sexual dysfunction barely altered.
For every woman who reported a sexual problem during the period, an equal number reported an improvement.
"We were surprised by the results," says Spector. "They suggest that menopause has been exaggerated as an excuse for everything."
It turns out the end of oestrogen isn't the end of sex after all.
If hormones are part of the picture, then changing attitudes to ageing are significant as well.
Dr Louann Brizendine, a top neurospychiatrist in the US and author of The Female Brain, claims that changes caused by the menopause weaken women's instincts to hold a family together and liberate them from the need to put up with second-rate husbands.
Brizendine also claims that a woman's brain chemistry changes in perimenopause, too - and that is to do with the feel-good hormone oxytocin (the one you get from having sex).
When oestrogen levels dip, so does oxytocin, making a woman less "we" and more "me" focused.
Combine this with a testosterone spike and you have a perfect storm for Chris Evert's "menopause-induced" affair. It also explains why more women than men in their 50s initiate divorce.
Things are looking up
As the list of women achieving great things - and looking amazing - in later life grows exponentially - consider the likes of Helen Mirren - post-menopause starts to look less like a slippery slope and more like an invigorating spin class that leaves you glowing and self-satisfied.
As Dr Holland says: "People have this idea that hormones cause behaviour, and this may be true. But often it's the other way round, and environment and behaviour will actually trigger hormones.
"Don't forget, libido is more in your head than anywhere else."
Even, it seems, when you're a menopausal, sexual write-off like me! Or Chris Evert.