“Ambitious, bohemian creatives, academics, that thought they were going to have this glamorous life, but here they are just struggling to get dinner on the table and the washing done, raise a family.”

Add sex work into the mix – something Rob paradoxically “finds sordid” although “he’s an active participant in the industry” – and it’s a recipe for resentment, heartache and dissatisfaction.

It’s a lot to grasp, this complexity. “That was really terrifying, to be honest,” he says.” Reading the script over and over, he wasn’t sure how to play Rob. There were sleepless nights, even before the read-through. “It was really challenging,” he says, this balancing act and cocktail of tonality. “It wasn’t one thing or the other.”

Rob’s grappling with contradiction and hypocrisy, while also trying to assert his position in the family.

“Rachel’s such a good actress that you’re afforded the luxury of trying all sorts of stuff but knowing it’s always going to be grounded with her,” he says. “There’s a safety net when working with people of that calibre.”

For the characters – the workers at Mack’s ethical brothel Sweethearts, a cast of talent that includes Johanna Cosgrave, Ariāna Osborne, Gemma-Jayde Naidoo, Carmel McGlone, Florence Hartigan and Moana Johnson; Danielle Cormack, Rima Te Wiata and Robbie Magasiva also star – and their place within the narrative, there’s a lot of grace shown.

The grey areas of real life and rendered in a believable, empathetic way; and like real life it’s dark and funny at the same time. “Life’s not black and white,” he says. “Not everybody’s bad.”

He worked on Rob. “It’s fair saying this, and the producers and writers would agree, when I got involved Rob was sort of the villain of the piece, and I was somewhat resigned to that,” he said. “It felt a little contrived that he was just this useless shithead off a husband.”

There was more there. “They were in love; there’s got to be something genuine about the man, something has to be redemptive.”

Henderson wanted to explore what that looked like. “The producers and the writing team were so collaborative and open,” he says. “That was a lovely part of the experience, the whole way through.” There would be rewrites and tweaks right up until the night before shooting, a testament he says to wanting to make the best version of the story they could. “That’s wonderful, it’s all you could ask for.”

Seeing the man in the antagonist, and understanding his motivations, disappointments, and dreams shows empathy, and it’s a sensitive portrayal of contemporary masculinity.

It wasn’t something he focused on when establishing his characterisation, not wanting to over intellectualise Rob or fall into symbolism. “That’s something for a post-mortem analysis.”

Motivations and what’s under the surface were more formative. “Who is this guy, what are his broken dreams, what heartache is he harbouring? Why has he gotten to this point where he’s gone outside his marriage?”

Henderson wanted to make Rob human, to make sure there was depth to the character. “You take a man that you could label as a version of toxic masculinity, and you scratch the surface a little bit, there’s probably a wounded boy in there that got raised by a dick of a dad.”

Is there pressure in our ideas of masculinity? “There’s such a conformity, whether you’re conscious of it or not,” he said. “You’re trying to abide by these rules and images of the tough guy.” It starts at an early age. “These boys are trying to conform to a gender role that’s subscribed to them by sport or history,” he says, but there can be a disconnect with their sense of self and identity. “Many men are just struggling with who they are.”

It’s prevalent. “Not to excuse abusive or manipulative behaviour that ensues from that,” he says, instead suggesting looking at things with a lens of compassion, and seeing neglect and abuse and how damaging that can be. “They’re trying to live up to this idea of being a man – whatever the f*** that’s supposed to mean.”

Born in 1974, Henderson grew up on Auckland’s North Shore, attending Westlake Boys. He grew up playing rugby, and loved it – the camaraderie, the physicality, picking yourself up. “Those aspects of masculinity are wonderful, but the problem is when you think that’s all there is.

Did he feel pressure around masculine ideals when he started acting, pressure to be a certain way, I ask. “Aside from being in the industry, just being a young male trying to form an identity.”

He was fortunate in choosing his career that it gave him scope to express feelings through his characters. “Things that if I wasn’t playing the character I’d probably keep very concealed, or ashamed of. “That gave me permission to own those parts of myself.”

Is there pressure around appearance, particularly when you’re presented as a heartthrob – like the appearance in the music video for Britney Spears’ hit Toxic, which he must get sick of being asked about. “Yeah, definitely,” he says. “You feel a sense of pressure, particularly now that I’m getting older, to be in shape.”

Henderson turns 50 in October. “I’m embracing it as a testament to my survival,” he explains. “I’m trying to be proud of getting older.”

He’s been sober for nearly 23 years, and doesn’t think he’d be where he is today if he hadn’t quit alcohol.

Understanding the motivations behind drinking was “so much work” and daunting at times, but the payoff was self-acceptance. “You ultimately end up with a lot of compassion for yourself,” and other people. “I feel at peace with who I am.”

Being active is a huge part of his life; surfing and spearfishing, kite surfing, a bit of bouldering and climbing. “It’s good for my mental health to be bombing down a mountain on a bike.”

A major source of happiness, it also creates space for connecting with friends, discussing their lives, rather than being “in the industry trying to make moves”. It helps maintain a sense of balance, and a life outside work – integral to longevity in an industry like his.

Landing in Hollywood, Henderson quickly identified the tensions and temptations of LA, its weirdness. “Most Kiwis feel something similar, because it’s just so foreign to how we live.”

Being there and playing the game, with all the relationships and meetings, is critical. “You have to be smart and savvy about the business side, but the culture was not very attractive,” he explains. “I never divorced myself from the industry, and I love the industry and feel very grateful for my career, but I didn’t want my life to be about that.

“Maybe my career has suffered to some extent because I’m not as proactively playing the game,” he says. “But you have to just be true to yourself.”

Acting as a profession that necessitates the commodification of self, I put to Henderson, not unlike sex work. Does he ever think about that? “Totally. I’ve sat around on sets joking about that with colleagues for decades.” They often use that analogy.

It’s an industry that relies on a certain level of self-obsession and self-promotion, but he doesn’t think that’s healthy. “It can be a very ‘me me me’ sort of job,” he says. “I’ve found it’s good to push against that.”

That’s easier said than done of course. You have to find a balance if you want to be a working actor; you can’t just pack it all in or self-destruct.

“I’ve probably been neglectful of my career,” he says, and also held on too tightly at times. “That’s the beauty of age, you get to experience what both of those realities are like.” Eventually, if you’re lucky, you find the golden mean. “Focus on the work and not yourself.”

Keeping a sense of perspective, or perhaps accepting what’s outside your control also helps. You never know what’s going to be a hit. Sometimes it’s something you’ll least expect, meanwhile “you do other things that are important and interesting and you’ve done great work, and no once sees it.”

Success is in the doing, he explains, discussing American playwright and screenwriter Neil Simon’s approach to work. “It’s about doing the work,” whether that’s studying your script or on set. “You have no idea if there is going to be an audience, but that doesn’t matter, because you can’t control that.” That’s where he puts his focus. “You don’t have to worry about yourself. Yourself doesn’t matter,” he says. “Try to do the best work you can, and hopefully someone likes it.”

The work has brought him back home. The past few years have seen him spend more time in New Zealand, though work still takes him overseas. “I am trying to be here as much as I can.”

There have been more local productions; as well as Madam, Henderson has appeared on Lucy Lawless’ series My Life is Murder.

Working back home has been great. “It’s great. It’s quite heartwarming,” he says. “Having grown up here, and growing up in the industry here at such a young age, there’s many familiar faces, going back 30 or more years.” It’s confronting, but lovely he explains.

Maintaining a connection to the New Zealand industry, and its storytelling, also carries weight. “It’s home, and my roots, and a privilege to have those opportunities.”

There’s something unique about the New Zealand sensibility. “The way we tell stories is just so particular.” It allows him to tap into a different part of his creativity.

Kiwi comedy is different – though not better than anyone else, he stresses diplomatically – drier and more sarcastic. “There’s a subtlety to our humour. You don’t always know that [something] is a joke.”

Madam is funnier than you might expect; comedy isn’t necessarily the first that comes to mind when you bring up ethical sex work and infidelity.

“You do hope that this might illuminate something, or change someone’s opinion, but if social media has taught me anything, I don’t think anyone gives a shit about changing their opinion.” But if someone were to take away something that changed their perspective, that’s great.

“Sex work and the industrialization of sex, the transaction of it, is a sticky issue,” he says. “Forget about sex work, sex in general we have such a complicated relationship to it as a society, morally, even within ourselves as a result of all that.”

Humour is a way to couch that. “You can laugh at it, which I think is healthy,” Henderson says. “But within the comedy and the lightness there is some real heartache, and I hope the characters are touching in a way that moves people.”

It may help shift perspectives on things, humanise something that can be laden with judgment or taboo, but you have to be realistic. “Some people are immovable,” he says, questioning how much change can be wrought by entertainment alone.

“The show is putting something out there that could lead to more constructive, open conversation, and maybe less prejudice.”

Madam premieres on July 4 on TV Three.

Emma Gleason is the New Zealand Herald’s lifestyle and entertainment deputy editor. Based in Auckland, she covers culture, media and more.