Commenting on her reaction to his former Sexiest Man Alive status, dry-witted Furness quipped: "[I tell him] Hey sexy, your turn for the garbage."
Over the years, they've been dogged by gay rumours on both sides of the relationship – a long-running whisper Furness never hesitates in rolling her eyes at.
"I see these magazines and they're so mean spirited. I hope people realise it's all made up. Nicole and Keith get divorced every week and I sit here and I'm like … they're perfectly happy. They just make up lies and they get away with it," she said.
She went on with a laugh: "[Hugh's] been gay for so many years, I was gay too when I did [1988 film] Shame. They were shocked when I got married.
"It's just wrong. It's like someone saying to Elton John, 'Oh he's straight'. I'm sure he'd be pissed!
"And so what! What are we discussing here … Is he a vegetarian … Is he gay?" she added of the obsession.
Elsewhere in the candid chat, Furness reminisced on the beginning of the couple's love story, describing meeting and falling for each other on the set of Australian TV show Correlli in 1995.
Recalling the "instant attraction" they had for each other, she said it wasn't until they were sitting in Jackman's kitchen one day when they realised they had fallen for each other.
"[Hugh] said he knew two weeks in," Furness said of how quickly their feelings grew.
"I remember I was sitting in his kitchen and he was cooking for a dinner party and I said, 'You haven't been coming into my trailer lately, we always used to hang out', and he goes 'Yeah yeah I know, I haven't, I've got a crush on you', then I said 'I've got a crush on you too' and that was it, we admitted it, and I don't think we ever spent a day apart.
"We just had this amazing connection and I feel blessed that I experienced it, I feel like I met my soulmate."
She continued: "When you find a partner and you find that you share and grow together … and we know, life is tough, it's not all good, but when you have someone there who is so supportive and you can really stand there buck naked and be yourself, authentic, warts and all, this is who you are. There's nothing better."
The couple adopted two children after tying the knot in 1996, after painful fertility difficulties dotted with miscarriages.
Their eldest son Oscar is now 20, and daughter Ava is 15.
"We were always going to adopt, and we were hopefully going to have biological children. I always just assumed that we would biologically have children but when that didn't happen..." Furness said, trailing off.
"I had many miscarriages. It's a loss," she added.
"It's hard. I always knew I was going to be a mother, I was raised by an incredible mother. It was instilled in me that I am very mothering, I like to nurture, so at the time, it hurt, it was painful. And then, you move on."
Reflecting on her relationship with her own mother, the late Fay Duncan, Furness welled up as she described her as an "amazing woman".
Duncan helped found the Fight Cancer Foundation, and was presented with the Order of Australia medal for her charity work shortly before she died.
"Everyone called her 'Mumma', even my friends. She was so warm and maternal," Furness said.
"She had ALS [motor neurone disease]," she explained.
"It basically shuts down your nervous system and you lose functions of speech, your body. I fought to the bitter end, and naively thought, 'No, no it's going to be okay'," she admitted.
Duncan died in 2016, and Jackman gave a moving tribute at her funeral, singing Quiet Please, There's a Lady on Stage from the musical The Boy From Oz.
