"It seemed so extreme, like something that would happen in a movie and not to our family.
"My mum was crying and calling out for Scott, and it was then that I realised this nightmare was true," Ms Guy wrote.
The family was interviewed by police as they grieved and their lives were turned upside down, she said.
Her then husband Ewen Macdonald was subsequently arrested on suspicion of Mr Guy's murder but acquitted in an extraordinary and high-profile four-week trial in Wellington three years ago.
Macdonald remains in jail for other offences including vandalising Scott and Kylee's new house, burning down an old house on the Guy family farm and the horrific killing of calves on a Horowhenua property.
Ms Guy wrote on Stuff.co.nz that the family had learnt a great number of lessons in the last five years.
"I still think about [Scott] every day and wish like crazy that he was here," she wrote.
"I don't sweat the small stuff anymore and even though there is still a long road ahead I know our family is strong and we will be ok.
"Life is precious and you never know how much time you have. So live well, laugh often and love much."
