But she said that they would consider all their options when it comes to parenthood and they haven't ruled anything out.
"David and I would love to have children, but, like lots of people, it hasn't been plain sailing so far. We're trying and, please God, we'll get there," she said.
"If it doesn't happen, we have talked about fostering or adoption. We've been so lucky in our lives so far that maybe having kids isn't meant for us, but we'll see.
"I have never been accused of not trying at anything so I will keep on trying at this until somebody says, 'Sinead, give it up!'"
The former newspaper journalist, who's also an avid keep-fit fan, went on to say how she has no doubt that the couple will eventually have a child.
"I have total faith that myself and David will be parents and I can't wait until we are. I keep thinking 'when is it my turn?' I'm so lucky in that Davie's on the journey with me. There are so many women out there that have to face the reality that it's hard to get there. I tell you what, when I am pregnant, the whole world will know about it. I'll be up on top of a mountain shouting it!"
She also revealed how how suffering a near-fatal brain haemorrhage changed her life forever. It's almost three years since she was rushed to hospital after collapsing on the set of the TV3 morning show.
Sinead spent two months recovering from the ordeal and explains how things will never be the same for her again.
"It has changed me, it's just taken me a long time to realise how. It has made me live my life much more purposefully. Whether it's career-related or personal I put great thought into everything I do. I ponder things a lot more," she said.
The energetic presenter explained to VIP magazine how the health scare was a "serious wake-up call" for her.