Alex said what was coming up was actually the real challenge.
"There are some pretty interesting couples on there," he said.
"The wedding is probably the easy part, it's what happens after when everyone else is gone and reality of life sort of kicks in - that's where it gets interesting. I think these couples are in for a bit of a rude awakening."
They also had some advice for the new couples, saying it was all about trust and hope.
The pair have had some difficult moments in the past year.
In June, 2015, Alex and Zoe told Nine Network's A Current Affair that they had had a miscarriage, according to the Daily Mail.
"Zoe fell pregnant and we didn't want to say anything because we hadn't reached that 12 to 13-week mark," Alex said on the show.
"It was the best news I've ever heard to be frank, I couldn't wait to share it with the rest of Australia. But unfortunately Zoe had a miscarriage."
As for the other season one couples, Clare and Lachlan told A Current Affair they were no longer together, according to the same Daily Mail story last year.
James and Michelle also called it off a few weeks after the show stopped filming, and Roni and Michael did the same - in episode five.
The Daily Mail said Michelle had since remarried a former love.
