"It's very, very devastating. All our hearts are breaking because he was just the most wonderful man," she told reporters.
"I left at ten past seven, and I was just pulling around to come into my drive and I get the call to say he'd taken his last breath at 7.22pm.
"So I missed him, but maybe he didn't want me to be there for his last breath."
Bert had been in hospital since May, when he underwent leg amputation surgery following complications from an infected toe.
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Despite his lengthy health battle, Patti said he "had such a fabulous attitude" and gave the family "so much joy" right up to the end of his life.
She shared regular photos of Bert in hospital to her Instagram, many of them showing the broadcasting heavyweight surrounded by their many grandchildren.
Patti said that their grandchildren were the "loves of [Bert's] life" and added that she's comforted to think that he's now at peace and no longer in pain.
Though the star had been battling health concerns for years, he had never formally retired from his Aussie showbiz career.
In fact, Patti revealed that he was still talking about his plans for future TV gigs before he passed this weekend.
"I used to laugh, because I'd think 'you're 83, you've got one leg, how would you go up and down the stairs?'" she said of her late husband.
"But I love that attitude of his, he was never going to give up and that's what we have to take with us, don't we girls [speaking to her granddaughters]?
"We have to just make sure that the love he gave us stays with us forever."
News of Bert's death shook the nation, with other big names in show business coming out to share their best memories of the TV icon.
Fellow TV star Rove McManus aired his heartache on Twitter, writing: "I don't know that I'm ready to accept this yet.
"Today I lost a mentor and friend, our country lost an icon, but most importantly a family has lost their hero and soul mate.
"Sending love to all the Newtons, especially Patti. My heart is broken. Rest In Power, Albert Watson Newton."
Meanwhile, Victorian Premier Daniel Andrews confirmed that Patti had accepted an offer to hold a state funeral in Bert's honour in the coming days.
The service will likely be attended by friends, family and countless other TV heavyweights who knew Bert best.
This story originally appeared in our sister site, Now To Love.