In Hollywood, older stars in "May-December" relationships aren't overly shocking. We're pretty used to seeing famous actors with grey-flecked hair arm-in-arm with young, gorgeous women.
Leonardo DiCaprio, 43, is currently rumoured to be dating 20-year-old model Camila Morrone; 35-year-old Scott Disick shacked up with a teenage Sofia Richie; and Rosie Huntington-Whiteley is 20 years younger than hubby, Jason Statham — but what about when adult kids are involved?
David Foster — patient zero of the Kardashian pandemic — is dating 33-year-old Katharine McPhee, making her younger than four of his five biological children, but they don't seem to mind.
His 35-year-old daughter, Sara Foster, told E! News: "We love Katharine McPhee. We love our dad. We want our dad to be happy. We don't care who he dates...don't really care how old they are."
"Honestly, our friends in their twenties are trying to date him, so we're just proud of him for not doing that," 32-year-old Erin added. "He's like, 'I draw the line there.' I think thirties, forties is like a respectable age for a man in his sixties."
But Hollywood is synonymous with unusual relationships; the shelf life of a celebrity marriage is presumed short, huge age gaps are the norm and successful stars can stay single forever.
However, in the depths of Tamworth, Barnaby Joyce's relationship with a younger woman didn't have that easy-going L.A attitude.
The conservative politician — who oft quoted the sanctity of marriage in the same-sex marriage debate — started an affair with his 33-year-old media advisor while still married to his wife. News of the illicit relationship exploded into the public consciousness when photos of a pregnant Vikki Campion emerged.
The entire relationship has become reminiscent of a soap opera as the backbencher continuously throws his new partner under the bus. He's claimed the paternity of their one-month-old is a "grey area", refused to describe her as his partner and insisted the only reason he agreed to the $150,000 interview on Sunday Night was because Vikki wanted the money.
Without the glitz and glamour of being a quirky Hollywood relationship, the whole thing has felt devastating, especially for his former wife and their four children — Bridgette, 20, Julia, 19, Caroline, 17, and Odette, 15.
These young women have had to deal with their parents' marriage breaking down, their dad shacking up with a woman unnervingly close to their age and had it all play out in the public eye.
Sarah*, 31, knows full well how devastating it can be to have your dad wind up with a woman far too close to your age.
"Three years ago, I found myself embroiled in the most clichéd affair story in the book — the boss who started sleeping with his PA," she told Cosmo.
"Only it wasn't me having the affair. It was my dad who started an illicit relationship with his employee. And, to add insult to injury, she was only five years older than me."
Sarah was (predictably) messed up by the discovery her dad was having an affair, but finding out she was young enough to be his daughter — her sister — "really fucked with my head".
As soon as heard about the affair, she took to social media to stalk the girl.
"She had similar style to me and went to gigs I'd go to," she confessed. "It felt like in a parallel universe, we could've been friends."
"But we weren't friends. She was with my dad. And it made me feel physically sick."
The thing Sarah found most disturbing was that her dad, well into his 50s, must've wooed this girl. She was forced to see her dad through a lens she'd never wanted to.
"He'd always just been my lovely dad," she argued. "The one who taught ME morals and the one to wipe away tears when I got my heart broken. Now he was the one breaking it."
Sarah was also heartbroken by how hard the affair was on her mum.
"She was a mess," Sarah sighed. "He confessed that he was having an affair after a few months — Well, that's what he said anyway.
"Me and mum are super tight and she confided in me straight away. I haven't lived at home for almost ten years so there were no obvious signs in my mind. But I was livid he could do this to my mum."
It was Sarah's digging online that revealed how young the new woman actually was, and she didn't want to be the one to break it to her.
"She was a shell after they broke up and I felt like I had to protect her," Sarah admitted.
"I'm an only child so had nobody who truly understood what I was going through. Friends understood my anger and agreed it was really creepy but I don't think they truly got how difficult it was for me."
Sarah's relationship with her dad also suffered in the wake of the affair.
"I've had an extremely strained relationship with my dad ever since. For the first year and a half I didn't see him at all. But I've since got married and it didn't feel right the man who'd been the perfect father for 28 years of my life didn't walk me down the aisle," she told Cosmo.
"Mum is doing better now, which obviously helps, and has met someone else.
"But things will never truly be the same with me and dad again."
All this time on, Sarah still hasn't met her dad's new partner.
"I've still not met her. Even seeing pictures of them together on social media makes me rage inside so I think it'll be a long time before I make peace with it — maybe I never will.
"It's very strange there's another 30-something woman who has my dad's affections — more so than his only daughter."
Sarah identified with Barnaby's daughters, especially given that they weren't given the option of privacy throughout the whole life changing ordeal.
"I can't imagine how Barnaby Joyce's daughters would feel seeing that interview televised to the whole nation. At least I could choose to tell people my father's misgivings if I wanted to.
"What I'd say to them? It's never not going to be weird. But you have to make peace with the man who brought you up and shaped your whole life — or else it'll eat you up."