"I knew he was an amazing boxer, and when someone of your kind does extremely well you're proud of them, but proud of them from afar," she said. "I said 'Tell me about your parents', and that's when we made the connection.
"He said he built his parents' place in Mangere and I said I did the same for my parents and it went from there. What was 15 minutes became two hours, and we built up a wonderful friendship, and it's been an amazing journey."
They married in January, and both partners believe a divine presence had a part to play in their union.
"Me personally, I believe that it was our parents' prayers," Tua said. "My parents prayed for someone that loves like me, and I'm actually quite privileged and very honoured to have someone like Helen.
"I'm the luckiest and most blessed man there is in the world, I never thought marriage could be this happy, happy every day."
The Tuas are investing their time running programmes out of Tua's gym in Onehunga that aim to inspire young people to turn their lives around.
"These are young boys and girls who have got themselves into trouble, and they've ended up in foster homes, in youth justice; when they walk in the door you can see instantly that in life something has happened to them," Helen said.
"We provide an environment where they can realise they're not the people that they've been told they are. They get told they're useless and that they'll never amount to anything.
"To see the changes, it is the most amazing feeling, that you could never put a price on. It's important that me and David are together, because they don't know what a good relationship is."
The programme incorporates fitness sessions run by Tua with inspiring talks and motivational sessions.
"There's a lot that goes on in this building that people don't know about. They just need to hear someone say they can do it, we believe in you, you do have what it takes," Tua said. "I could've been one of those kids."
The desire to help those in need is behind Tua's Park Up event. He lived in a car for six weeks in Florida in 2009 when his American promoter ran out of money.
"Living in a car myself is one thing, but all that aside it's about doing what's right for the people who are without homes right now.
"It affects all of us. As a staunch community leader, it's about standing up and doing what you believe is right."