Portrait of a marriage, by a neurotic spouse

Appignanesi subsequently finds the document and gets on a (much) later flight. But thereafter, instead of displaying remorse and contrition and generally being as supportive as he can to his wife on her big book tour, he aggressively records the tour instead.

“I’ve got a book coming out, and then suddenly he’s making a film. He’s been cast in a supportive role, and it’s not one he suits easily. He likes to be the protagonist,” laughs Baum. Appignanesi laughs too.

This is a filmmaker (Song of Songs, 2006, The Infidel, 2010) who knows how to send himself up. It is a comic self-portrait that he offers in Husband. On camera he is an insufferable mix of needy, controlling and hysterical — the very feelings Baum unpacks in her book.

When I interview them he’s every bit as likeable as his lovely and collected wife. And they are both very funny.

But the questions they ask in Husband are quite serious. “Does anyone want existence to be defined by their relationship to someone else?” asks Baum when we meet. And yet for millennia this has been women’s lot, of course.

They have been left holding the baby while men make their way in the world, and women quietly support them in the background.

“We’re so used to seeing this, it feels natural. But I’m not sure it’s easy to be in that role without consciously or unconsciously resenting it,” she says. By the end of the film, Appignanesi attests to his resentment.

“I realise that I’m the one who’s having all the feelings stereotypically associated with women, who is feeling the way that women are accused of feeling. I admit that actually my wife is cool and calm and I’m the one who’s a mess, who loses everything and who’s neurotic,” he says.

The point being, of course, that men and women are not stuck in identity silos, there’s always slippage. And that even when men and women are stuck in roles, there’s invariably a performative quality to their role-playing.

Of course, to recognise this, to look inwards, you need to be feeling insecure in some way, notes Baum — “the main thing fascism sets itself up against is introspection, The fascist condemns that person who looks inwards to wonder who they really are.” It is why, she explains, the interrogation of the self is such familiar trope in Jewish literature.

This is the second time this couple have bravely interrogated their relationship on screen. Husband is the unofficial sequel to The New Man, which they co-directed and co-produced in 2016, about their experience as expectant parents.

Looking at pregnancy from a mostly male point of view, it charts 21st-century-man Josh as he faces first-time fatherhood in his late 30s after a series of fertility treatments, a happy, funny experience that unexpectedly lurches into tragedy when one of their twin boys dies in the womb.

The result was moving, relatable and very honest — as is Husband, the sort of openness that takes courage, I suggest.

“Yes it is scary,” admits Appignanesi. “I mean, why would you put yourself through it? But we’re quite proud of it.”

‘Husband’ is released today, JW3 is hosting screenings from February 13 to 19 In cinemas and on Curzon Home Cinema from 10 February"