Jane Thompson said husband Shaun had tried to blame her for Kieran's death
A soldier has been jailed for five years after pleading guilty to the manslaughter of his 21-month-old stepson, saying he lost his temper.
Kieran Edwards, of Market Drayton, Shropshire, died in hospital three days after suffering a brain injury at his home in June 2007.
Shaun Thompson, 25, of the Royal Anglian Regiment, denied murder.
Experts said Kieran must have been subjected to shaking or a traumatic event, Stafford Crown Court heard.
The court was told Thompson had denied playing any part in Kieran's death for two years.
Kieran died as a result of a sudden loss of temper by the defendant
Mark George, QC
Prosecuting, Rachel Brand, QC, said Thompson had met Kieran's mother when his regiment moved to Tern Hill barracks in Shropshire, in late 2005.
On Sunday, 24 June, 2007, Kieran bumped his head after falling on to tiles at the couple's home, but doctors later said this accident had nothing to do with his death.
She said Thompson had cared for Kieran alone during the evening while his wife went out with a friend.
Thompson at first denied anything violent had happened to the boy, but changed his account after his arrest on suspicion of murder in May 2008.
In mitigation, Mark George, QC, said Kieran had died as a result of a loss of self-control.
"It was two years after Kieran died before the defendant finally acknowledged that he - and he alone - was responsible for the injuries that caused Kieran's death," he said.
He added that the evidence in the case is that Mr Thompson had been a good father to Kieran.
"Kieran died as a result of a sudden loss of temper by the defendant - who did not intend to cause really serious harm, let alone any injury causing the child to die."
Thompson, who will be discharged from the army following his conviction, could also be divorced by his wife.
Speaking after the hearing, Jane Thompson, who had also been arrested on suspicion of murder, said it was plain that some incident involving substantial violence had happened while her husband was looking after Kieran.
"By his plea of guilty to manslaughter Shaun Thompson has at last accepted responsibility for this shocking act after a protracted period of trying to blame me for what happened," she said.
She added the five-year sentence was inadequate although she accepted it was in accordance with the law.
"Shaun Thompson has deprived my much-loved son of his life and this is something with which I am having the greatest difficulty in coming to terms with."
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