Nadene Lomu posted a heartfelt message on social media on Wednesday, saying her “insides are hurting and crushed beyond repair”.
Lomu, 40, died unexpectedly at his Auckland home on November 18, 2015 of a heart attack, which was linked to his rare kidney disorder.
The giant wing had not long returned from Dubai, where he had been holidaying after the Rugby World Cup in the UK, when he collapsed and couldn't be resuscitated.
“Never would I ever thought a single person could shred my heart into a gazillion pieces, pieces that could never be put back together fully," Nadene posted on Facebook.
"To this very day, 5 years ago that's exactly what happened....Jonah, you tore my world apart with your departure to the point I struggled to breathe ....I know you'd give anything to be here with your boys and I right now, as I would too...just one last anything, everything you ever wanted for us and more, all that we were working for together.
"There's not a moment that I don't wish you were still here. I feel sick, I'd rather sleep the entire day away and wake up the next morning just to get through but I can't, I can't because your boys need me to be their pillar of strength, they need me to smile even though my insides are hurting and crushed beyond repair.”
Lomu had battled kidney disorders since the end of 1995 when he was diagnosed with nephrotic syndrome.
He had a kidney transplant in 2004 and suffered health setbacks during the 2011 Rugby World Cup in New Zealand.
At the time of his death, former All Blacks doctor John Mayhew described it as "a bolt out of the blue", especially as the man who took the rugby world by storm 10 years earlier, at the World Cup in South Africa, had been in good shape in the months previous.
Lomu and Nadene had two sons together: Brayley and Dhyreille, who were 6 and 5 respectively when Lomu died.
"In my moments of weakness you are my strength, I hear you, I feel you and I know you are watching over us and you still walk by my side,” Nadene's tribute continued.
"I will always stand to be your voice for what you wanted and believed in but most of all, I stand with your strength to be the best I can be for your boys like you asked me too, no matter what, no matter who thinks they know better.
"I will always love you Jonah, my heart will always be yours and our boys will always be my everything in this life and the next, till FOREVER. Yours truly."
Lomu was the youngest All Black debutant – 19 years and 45 days - when he first played for the men in black in 1994.
He went on to score 43 tries in 73 tests. He last represented New Zealand in 2002.