A former political editor for 3 News, and presenter of Story and 3D, Garner has three other children from previous relationships.
Garner declined to be interviewed, saying the split was "a private matter".
Last year Garner shed 12 kilos and is now a regular at group workouts around Auckland. In an interview with Woman's Day last year he credited his weight loss and general wellbeing to Delamere.
He said he was "a much happier and relaxed person, and a better father and husband" for going to counselling sessions.
"Like lots of guys, I used to think getting therapy was a sign of weakness, and that I just had to harden up and push through, but it's the best thing I've ever done and I wish I'd done it earlier.
“I might sound like a hippie, but I’ve learned you can still be real man and seek help,” he told the magazine.