A man tried to kill his partner and her mother after taking a "lethal cocktail" of alcohol and cocaine following a birthday night out, a court was told.
Simon Cragg lured Janet Platt, 53, downstairs at his house in Woolston, Warrington then repeatedly stabbed her.
He then knifed his girlfriend Natalie Platt, 29, when she heard her mother's screams and went to investigate.
Mechanic Cragg, 31, who admitted two counts of attempted murder, was jailed for 16 years at Liverpool Crown Court.
Judge Clement Goldstone QC said Cragg had consumed alcohol and cocaine on the night of the attack to self-medicate his depression.
"That cocktail of alcohol and cocaine was lethal," said the judge, who expressed surprise at Cragg's actions given that "he had never displayed any signs of violence" and had been "a model partner and son-in-law".
He said: "No-one will ever know why you should have chosen to behave in the way in which you did. Leaving Miss Platt and Mrs Platt to bear massive physical and psychological scars.
"You shattered the illusion you had built up over 11 years."
Prosecuting, Anya Horwood said that when Miss Platt managed to get hold of the knife, Cragg placed his hands around her neck and squeezed so tightly she thought she was going to pass out.
Following a struggle in which she was head-butted and again stabbed, she managed to kick him away and escape their Alder Road home to raise the alarm.
Mrs Platt suffered "life-threatening injuries" which included 15 stab wounds and two tears to her heart, the court heard, and she spent several weeks in intensive care.
After the attack, Cragg was found in his garage threatening to kill himself with a chainsaw, knife and axe. He had inflicted deep cuts to himself.
Jeremy Rawson, defending, said: "He is brimful of remorse and regret. He has no recollection of what took place."