The Canberra couple completed a civil union in 2009, wed under landmark ACT same-sex marriage laws in 2013 and are preparing to do it all again in 2018.

After results in the national postal survey were published last week, the couple contacted Canberra-based wedding celebrant Judy Aulich to start planning for their third, and final, ceremony.

Ms Aulich has worked with them each time, sharing their disappointment when the High Court overturned the ACT laws.

Once the new law is enacted, couples will be required to give 30 days notice of their intention to marry.

"We haven't firmed up the date, but it will either be early January to get in with all the excitement of it passing and the first lot of weddings, or we'll do it on the Canberra Day weekend in March," Ms Cox said.

"We're really very happy Canberrans and that's why we were so pleased when Katy Gallagher and Simon Corbell put the legislation through in 2013.

"It was a progressive government that recognised the importance of taking risks and introducing legislation to meet need."

Like thousands of same-sex couples around Australia, they watched closely the results after months of excitement and anxiety about the process.

"We weren't together on the day," Ms Cox said.

"I was in Sydney for a meeting, Liz was at work. I went to Prince Alfred Park for the Sydney celebrations with a few of my board colleagues, so we could all hear the announcement together.

"When we were together quite late that night, the relief just washed over us. I felt very unwell, sick in the guts before the announcement."

Ms Holcombe said the couple had avoided much of the coverage and social media commentary during the campaign after they became angry and concerned about the tenor of the debate.

"What's the old saying? Never read the comments. It was a good and useful piece of advice for the last couple of months," she said.

"It was quite nerve-racking. The emotion expressed by Penny Wong and David Marr was similar to what I felt. There was intense relief after it became apparent that the 'yes' vote had won comfortably.

"One of the things I was worried about was that the 'yes' vote would win narrowly, like 51 per cent or 52 per cent.

"That would have been very difficult."

About 47,000 same-sex couples reported living together in Australia in the 2016 census, with same-sex marriage promising to provide a billion dollar boost to the country's already growing $6.3 billion wedding industry.

"Love is love. It's one of those things, you grow up and have the rite of passage of marriage to the person you love and you build your lives together," Ms Cox said.