Why do we find middle-aged sexuality so confronting?

I had the sub-titles turned on when I was watching the first episode of Apple Tree Yard (kids).

"His belt buckle rattles." (Take note: weirdly loud belt. Macho?)

She breathes heavily.

Bucket rattles.

(They are in a broom cupboard.)

They pant and moan. Bucket continues to rattle. He moans. He moans loudly.

Afterwards, scientist Yvonne Carmichael, aged 50-something, who has just had sex with a handsome stranger while hanging on to a coat hook says: "I've never done anything like that before."

Dr Carmichael (oh yes, Doctor) is married, although her husband Gary signs his texts "see ya", not even a kiss, so he deserves to be cheated on really, what with his working class name and the fact he doesn't even seem to know that tins go in the recycling. Not to mention his boring sinuses: "What's the name of the nose stuff? Drops. Gary."

He has subtitles too. "He snores. A beat. Snoring continues. He grumbles."

It's pretty hard to compare "You don't need to be home in time for the Tesco delivery" with "You're beautiful. Take your knickers off."

So yes, plot twist, soon Yvonne is back with Mr X in a cafe toilet. And a graveyard. And an alley way. (The eponymous Apple Tree Yard).

Subtitles: She pants. Belt buckle rattles. (Again.) They pant. He moans.

Later, while the couple are adjusting their clothes, two hot young girls walk past. They snigger. Yvonne crumples and tells Mr X they should stop the affair. She feels absurd.

"Well look at me! I'm middle aged and my body ... I look like a bloody jelly baby."

Later Mr X signs his text "JBILF"

"JBILF?"

"Jelly baby I'd like to ..."

Just to catch you up, Apple Tree Yard is the hit drama about a middle-aged woman, an eminent scientist, played by Emily Watson. After giving evidence to a select committee she meets a handsome stranger (Ben Chaplin) who offers to give her a tour of little-seen parts, ahem, of the House of Commons.

"Have you seen the chapel in the crypt?" could become Private Eye's new wink-wink leg opener (It used to be "They were upstairs discussing the Ugandan situation.")

Without finding out his name, Yvonne succumbs - no, that's the wrong word - enjoys, a knee-trembler in the broom closet. (It has a plaque commemorating how a suffragette hid there. This is not sordid; it's made by the BBC.)

So begins Yvonne's secret affair.

In her respectable day-to-day life, Yvonne and husband Gary are boringly mating in captivity like upstanding Guardian readers who own the full complement of wooden salad bowls and Le Creuset cookware.

There is a swimming pool scene because shows about adultery always seem to denote sex with water (I guess no one likes it dry) but in this pool there are no discarded plasters or pesky disabled people.

Instead, there is a wacky best friend called Suzi, which gives Yvonne the chance to get her misgivings about her waning sexual capital on screen.

No matter how good our scaffolding - $400 highlights, Helmut Lang silk shirts, pelvic floor exercises, Guerlain foundation with flattering gold flakes - we are terrified we are not hot, we are not even JBILFs anymore.

Yvonne asks her friend: "Still attractive. Do you think that's what they say about us?

She confides that sex with Mr X is "like being eaten by a wolf". This could be an entry in the Bad Sex Award ("Heloïse has lost all sense of how she ought to behave ...")

But on the contrary. I find it extremely horny. Not because of the heavy breathing but the fact there is so little talking.

"You were very articulate in there, Professor," is all Mr X says when he meets Yvonne for the first time. Eight words. Five minutes later he is undoing his belt.

Whereas you know, in real life, it goes more like blah, blah, blah - "You've got a Seiko watch? I've got a Seiko watch!" - and so on and so unsexily on with protracted negotiations about commitment and Netflix.

But in Apple Tree Yard they have sex first and talk later. And even then not much. Yvonne says: "Isn't this all a bit back-to-front?"

After they have had sex she notices his wedding ring.

"You're married."

"So are you."

"Should we just skip all that?"

And have sex in the cafe toilet? Hell yes.

The lack of talking may come as a relief to most people who have been married for decades. Twenty years, that's a lot of pretending to be fascinated and discussing the recycling. (No coincidence, Yvonne is putting out the plastic bottles when she decides she wants to see Mr X again.)

Mr X doesn't talk much, but he just looks. It's all in the eyes. That sense of being totally seen, being accepted and adored, is the best drug in the world.

No wonder women loved this show. It's what most of us miss the most. It's not the sex. It's being truly seen.

In the UK the response to Apple Tree Yard was that "the cultural topic of sexually powerful women in their 50s is now open for business."

The show was widely congratulated for giving a starring role to Watson, who is 50, and not making her a stuffy pearl-clutcher.

So I think when the editor asked me to write this piece, what she had in mind was something fortifying about how the taboo of sexy women over 50 has been lifted. It's no longer subversive, who-just-farted shameful for a woman of menopausal age to be sexual.

Um. Not so fast there, soldier. Hold the confetti.

No matter how good our scaffolding - $400 highlights, Helmut Lang silk shirts, pelvic floor exercises, Guerlain foundation with flattering gold flakes - we are terrified we are not hot.

Yes Yvonne Carmichael wears cardigans with just the right amount of cleavage and is not at all muttony. Yes, she gets to have bucket-rattling sex.

But. But. And it's a big but. She then gets brutally raped by a colleague but somehow she
ends up in the dock.

Maybe the message of Apple Tree Yard is not so much one of sexual empowerment but a modern cautionary tale. Take what you want, but pay the price.

Yvonne got to have dirty-movie sex and hang on to coat hooks with ecstasy because later, wow, did we ever make her pay for it.

Yvonne got raped by her colleague who taunted her - "Does your husband know you're cheating on him? - but didn't tell anyone. The subtext: at 50, who would want to rape you? (Incidentally the rape victim in Broadchurch was the same age and got precisely this response from another character.)

After that rape scene Yvonne was wishing to go back to unpacking the Tesco groceries and living with her boring husband's snoring. Where's the uplifting message now?

Being seen and desired may be a bigger high than crack cocaine, but when reality intervenes it is just as brutal. The message I took from Apple Tree Yard was far from a rallying cry for the modern, zipless f***. Instead it was act your age. Don't go into broom closets with strange men.

The highs are not worth it. And a woman's sexuality is still something shameful.

Yvonne says: "You made me feel special. But I'm not special. I know what I am now. Nothing."

Women are still to be pitied for letting it all go or we are to be pitied for being sad cougars chasing our youth. There is still no place in between: to be beautiful, to be seen, to be loved.

Apple Tree Yard is screening now on TVNZ 1.