Frederick Gilliard, 76, told officers he “just lost it” after having a blazing row with Josephine, his wife of 54 years.
Gilliard was suffering from a “depressive episode” at the time of the attack, Preston Crown Court heard.
The couple were a decent, hard working couple who raised four children and had three grandchildren, the court heard.
Mr Gilliard had also served in the RAF for 27 years including seeing active service during the conflict in Aden.
Members of his family wept in the public gallery as he was jailed.
His depression and rows tipped him over the edge and on February 5 2012 he used a garden figurine, in the shape of an Easter Island monolith, and an eight inch carving knife, to kill his wife, the court heard.
Mrs Gilliard, 74, who was known to friends and family as June, suffered “catastrophic” head injuries and 10 stab wounds of “considerable force” to her neck, chest and stomach.
After the attack, he then dialled 999 telling the operator “I just lost it” summoning police to the family home in Links Road, North Shore, in Blackpool, Lancashire, where officers found his wife lying face down on the bed. The knife was lying next to her.
Gilliard told the officers: “I can’t believe it. This is going to kill my kids. We have been married 54 years. I loved that woman.”
The pensioner was originally charged with murder but at an earlier hearing pleaded guilty to manslaughter on the grounds of diminished responsibility due to his depression.
Passing sentence Judge Anthony Russell, QC, Recorder of Preston, told the defendant: “This is a terrible tragedy which has affected all of your family and you, and must have inflicted considerable emotional damage which can never be repaired.”
Frail Gilliard, who walks with a stoop and wears glasses and hearing aids in both ears, could not hear proceedings and looked over to his family in the public gallery who held up four fingers to indicate the sentence.
Stuart Denney, prosecuting, had earlier told the court that Gilliard had suffered from depression a number of years earlier but had stopped taking tablets prescribed for him by doctors.
He said Gilliard had got the garden figure, which was designed to look like an Easter Island statue, from the garden and the knife from the kitchen before going upstairs to attack his wife in the bedroom as she lay on the bed.
He added: “It was clearly a prolonged and violent attack.
“During the 999 call the defendant told the operator he had just killed his wife, smashed her head in and stabbed her following a blazing row. He just lost it.”
Mr Denney said the psychiatrists who assessed the defendant “were of one voice” that the pensioner had suffered a depressive episode.
Andrew O’Byrne, mitigating, added: “Just under a year ago a relationship that had endured in excess of 50 years between this defendant and his wife came to an abrupt and violent end.
Outside court Detective Superintendent Ian Critchley, who led the investigation for Lancashire Police, said: “This was a tragic crime which has left a whole family devastated by their loss.
“Our thoughts are with the Gilliard family at this difficult time.”