Batley and Spen MP Mrs Cox, 41, was killed by far-right extremist Thomas Mair outside her constituency office on June 16 last year.
He was later handed a whole-life prison sentence for the Labour MP’s murder.
Nearly a year on, Brendan Cox has spoken of the impact of her murder, describing the moment he heard about her death as like a “grenade going off inside me”.
Mr Cox, 37, was in London when he heard his wife had been injured and got on a train heading north.
It was during this journey that Mr Cox received another call from his wife’s sister Kim Leadbeater to say Mrs Cox had died.
Speaking of that moment, he told the Mirror: “It feels like an explosion or a hand grenade going off inside you. And then you’re a just a shell really and retreat into shock mixed with collapse.”
Mr Cox said he was advised to tell his children - Cuillin and Lejla - about the news and to be as open as possible.
Writing in new book Jo Cox: More In Common, he said: “I had to say, no, I couldn’t dream up a way to bring Mummy back to us.
“I explained to Cuillin that his good idea that scientists might be able to inject life into her wouldn’t work.
“We also couldn’t make a new version of Mummy out of wood, as Lejla had suggested, and we weren’t going to see her in another world.
“I told them that Jo was gone but that she lived on in our hearts and heads.”
The children asked Mr Cox why someone had killed their mother - with the widower replying it was because the person who killed her didn’t want her to help people.
“I am maybe 20 per cent down the road of dealing with it. There are still thing every day that make it bite deeper,” he told the paper.
Tens of thousands of community events will take place on June 17 and 18 as part of the Great Get Together which has been created by the Jo Cox Foundation and The Big Lunch.
Organisers have said they hope the celebrations will be the biggest since the street parties held to mark the Queen’s Diamond Jubilee and will be a chance for communities to celebrate what they have in common.