Rhys Hancock appeared before Derby Crown Court on Thursday, October 1, after admitting the murders of Helen Hancock and her new partner Martin Griffiths at a hearing in July.
The court heard that Hancock, 40, had gone to the home he had shared with his wife and three children in New Zealand Lane, in Duffield, near Belper, and stabbed Mrs Hancock a total of 66 times in different parts of her body.
The former headteacher had been staying with his mother prior to the attack in Etwell, Derbyshire, after being placed on police bail following an earlier alleged attack on his wife.
The court heard that Mr Griffiths had been stabbed a total of 37 times and later died from his injuries sustained.
Prosecuting, Michael Auty QC told the court that Hancock had only discovered the new relationship when his children went to stay with him on Boxing Day last year, when they told him Mr Griffiths had visited the home of Mrs Hancock’s sister on the evening of Christmas Day as part of a wider family gathering.
He had become increasingly unhinged in the days that followed and announced to his mother at around 4am that he intended to travel to Duffield and kill the new couple.
He then took his mother’s panic alarm, attempted to rip the internet cables from the wall and frisked his mother, looking for the mobile phone.
He then left the property with two large kitchen knives, along with both of his mother’s house phones and drove to Mrs Hancock’s home, the court heard.
His mother managed to find her mobile phone and called the police, who tried to call Mrs Hancock to warn her, and officers were dispatched to the scene - but Hancock had carried out the murders before they arrived.
Judge Nitmal Shant QC sentenced Hancock to serve a minimum of 31 years before he can be considered for parole.