Rob collapsed after going to bed early with flu-like symptoms at his home in Newport, Gwent.
Two hours later Dianna heard him struggling for breath through a baby monitor she keeps on the upstairs landing and by the time she reached him Rob was taking his last breaths.
Dianna, 29, said: “I said my goodbyes and told him I loved him and then watched as he died in my arms.”
She dialled 999 and was told how to try to resuscitate him as an ambulance was alerted.
Dianna also shouted to next-door neighbour Gary Thompson who helped her desperately perform CPR for four minutes until the paramedics arrived.
They then used a defibrillator to shock Rob’s heart six times without success.
As the minutes clicked by they tried one last time — and he suddenly started breathing again.
He was then rushed to hospital where he was put into a medically-induced coma.
Doctors warned her that even if he pulled through it was likely he had suffered serious brain damage.
She said: “I started grieving because I thought there was no hope, I didn’t know what I was going to tell our two young sons.”
Three days later Rob shocked doctors when he opened his eyes — but he failed to recognise Dianna who was keeping a bedside vigil because his brain had been starved of oxygen.
But amazingly the next day he woke up and asked nurses: “What’s my wife doing sleeping on the floor?”
He gradually began to piece together his long-term memories and three days later was well enough to see his children, three-year-old Mylo and Koby, one.
Dianna said she will always be grateful to neighbour Mr Thompson and paramedics Dan Faulker, Alan Hodge and Gary Evans.
“I am so grateful that the paramedics carried on working on him.
“They didn’t just save Rob’s life, they’ve saved mine and the children’s as well.”