Sade Apiata has told the women's magazine how she felt trapped and isolated living in a rural south Auckland community while Willie was often away on charity work. "I was very isolated and lonely," she said.
Although the pair tried to reconcile in October 2015, after several months' separation, Sade Apiata said things were still no different.
"Willie asked me to come back. We both still loved each other and really wanted it to work... He was like 'Just be patient, your time will come'," she told Woman's Day.
"But it felt like it was taking forever. He really wanted to live the quiet life, whereas I'm still young and still needed to grow myself, so that put a massive strain on our marriage."
Apiata was pictured with another woman, whom he wouldn't name, at the Halberg Awards in Auckland in February this year.
Apiata is the only living New Zealander with a VC, the highest military honour. He won the award for rescuing an injured fellow soldier under enemy fire in Afghanistan in 2004.
Prime Minister John Key announced in 2012 that Apiata would be leaving the Defence Force to work for the High Wire Trust in Papakura after a 23-year military career.
In a statement, the soldier said family played a big part in his decision to leave the Special Air Service.
"This has been a decision that I have not taken lightly and it is one that has taken me many months to make. I am leaving to pursue my goals and to grow with my family."