"No, I haven't been having an affair and getting divorced wasn't in my plans, but I did need to break the cycle of dysfunction and give our sons the very best chance in life that I could.
"It is hard to know where it goes from here as there are so many issues that need to be addressed."
He said he was "so different" to Lisa, claiming he is "health conscious and responsible", while suggesting Lisa is not.
Speaking to News.com.au about the split, Lisa admitted the situation was "awful".
"All of a sudden, I didn't have a roof over my head, I didn't know where I was going to live.
"I never expected that to happen to me," she said of her difficult financial situation.
The former reality TV star said while she always earned "good money", she wasn't savvy as David managed the financial side of life including making mortgage payments and arranging school fees for their sons, Bert and Harry.
"David always paid the bills and did the budget. We both had different skill sets - there was nothing untoward about it, but numbers bored me."
She is now dating businessman, James Laws.