It was during her university years that Janet Rice first met her future wife, then known as Peter.

The young climate activist and future Nobel Prize winning climatologist dated for three years before tying the knot, settling down in their hometown of Melbourne to chase respective careers in politics and science.

It would be another 16 years of marriage before Senator Rice learned of her then-husband’s secret.

While it came as an enormous shock, Senator Rice said the biggest surprise was that her partner of almost two decades had managed to keep cross dressing a secret.

“The biggest shock was I thought I knew everything about Penny,” she said.

“She told me that she was a cross dresser and then over the next couple of years, she realised very much that she was transgendered and wanted to transition. It was a big time of our life.”

Dr Whetton began transitioning in 2003, a process which can take anywhere between several months to several years.

The life changing process coincided with increasing media scrutiny on Senator Rice, who was heavily involved with local politics as a councillor for the city of Maribyrnong at the time.

Though balancing public and private life was a challenge, Senator Rice said their relationship was never something she wanted to hide.

“It was something that we certainly felt we wanted to be open about,” she said.

“For people coming out as being gay, they know there are some people who won’t accept them. For Penny coming out as transgendered, for us as a couple, we went from being the perfect ordinary marriage to suddenly being interesting.

“But for us, it meant we were able to show the world that these things happen, everyone’s different and this diversity is something that we should be able to celebrate.”

'The biggest shock was I thought I knew everything about Penny'

It’s a revelation that has ended marriages before, but Senator Rice said splitting was never an option.

She described it as more of an adjustment, telling media at the time that “for me, it was saying ‘oh, I’m a bisexual’.”

She told SBS that “it was pretty big, but we got through it”.

“For me, I loved Peter,” she said.

“It was a challenge because it was the sort of thing you don’t expect to happen, but we got through it. There was that realisation that I still love her, we can stay married. That was it.

“To actually think of her as Peter now is extraordinary.”

Her words echo those laid out in her maiden speech, delivered last year.

Speaking in the Senate in August, Senator Rice declared her intention to put her motto of “love is love” in law.

“The time for marriage equality in Australia has come,” she said.

“I'm here for all lesbian, gay, bisexual, transgender and intersex people and their families. We deserve recognition and respect in all aspects of our lives.”

‘To actually think of her as Peter now is extraordinary’

“It gives us a very unique position, to know that having been in both heterosexual marriage and now a same sex marriage that they’re one in the same,” she said.

“We’ve got that experience to know that Penny having transitioned from being Peter to being Penny, she’s the same person. We still love each other.

“We loved each other when we got married. We loved each other when she transitioned. We still love each other now.”

Senator Rice described the current situation in Australia as frustrating, with several attempts to legalise same-sex marriage failing in both parliament and the courts.

“Why don’t we just get over it?” she said.

“We shouldn’t be still talking about this stuff. Regardless of people’s sexuality or gender, if two people love each other, they should be able to get married.

“Full stop.”

Their status as a legally married same-sex couple in Canberra is rare, but that could change in coming months.

Senator David Leyonhjelm is pushing for an open debate on marriage equality, threatening to block government legislation if the Coalition doesn’t allow a conscience vote.

It will be welcome news for same-sex advocates in Australia, though any legal changes will trail numerous countries, including neighbours New Zealand.

‘We’ve got a great rivalry with New Zealand and we’re losing’

Since legalising same sex marriage in 2013, New Zealand has wed dozens of Australian couples who ventured across the Tasman, including Mark Tayar and his husband Ray Chow.

The couple wed earlier this year, three years after their engagement began.

Mr Tayar told SBS that while it was disappointing to leave home for their wedding, they “decided it was time to stop waiting for Australia to get in the act”.

He said being treated “like any other married couple” was overwhelming, even if the feeling didn’t last when they returned to Australia.

“To come home is a bit of a kick in the teeth,” he said.

“It’s terribly frustrating that Australia doesn’t recognise us as a married couple. I think the Australian public recognise us and want gay marriage to be recognised, but the government is lagging behind.”

Mr Tayar joked that their wedding must have been “blessed by someone”, with his mother walking him down the aisle in perfect weather.

He said he and his husband would have another ceremony if same-sex marriage was legalised in Australia, but until then, they would continue their private protest.

“It’s our responsibility to be a little bit political,” he said.

“We’re not activists by getting married, but it is a passive form of activism I guess. Going over and saying ‘screw you, Abbott, we’re getting married in Queenstown’.”

For a report watch SBS World News on Saturday at 6.30pm.

(Images of Janet Rice and her wife are stills from a promotional video posted on YouTube by the Greens.)