Thomas Court turned up at his ex's home in South Shields on February 24 and barged his way in, locked them both inside and put her house key in his pocket.
The 34-year-old then removed the battery from the woman's mobile phone and armed himself with a large kitchen knife from a drawer.
Newcastle Crown Court heard Court, who received an earlier prison term for attacking the same woman and her grandmother in the past, then warned his victim "sit down or I will butcher
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During the three hour imprisonment, Court talked "nonsense", helped himself to food and then lay down in bed, which gave is victim the chance to escape from the house, bare foot and
She told police after the ordeal: "I was left absolutely terrified by it.
"I didn't give him permission to come into my house. I just want him to leave me alone.
"This whole incident has left me terrified to live in my own home.
"It feels like the only other thing he can do now is kill me."
The court heard the victim had been in bed when Court turned up at the door and barged his way in when she opened it.
Prosecutor Neil Pallister told the court: "Having armed himself with the knife, he told her 'sit down or I will butcher you'."
Mr Pallister said the "terrified" victim kept Court talking in a bid to calm him down and said he appeared "paranoid"
He added: "He was stroking her knee while talking and holding the knife in his other hand."
The court heard after Court declared that he was hungry and helped himself to something to eat he announced that he was tired.
Mr Pallister added: "He came out of the kitchen and said he wanted to lie down.
"He told her to come with him.
"He told her to lie down on the bed and she said she would only lie down with him if he put the knife down.
"He put it down but she was conscious he had his hand over the side of the bed and kept touching the knife.
"He fell asleep."
The court heard the woman ran for help and Court was still in bed when the police arrived to arrest him.
Court, of no fixed address, pleaded guilty to false imprisonment and using violence to secure entry.
Judge Amanda Rippon sentenced him to 18 months behind bars.
The judge told him: "You armed yourself with an extremely ugly, large and extremely dangerous knife.
"You went into the sitting room, where he was, and told her you would bother her if she didn't do what you said.
"She said at the time she was absolutely terrified by the incident, which is hardly surprising.
"She was terrified to live in her own home and felt the only thing left that you could do is kill her."
Jacqueline Coxon, defending, said Court may have been suffering from psychiatric illness at the time of the offence and has mild, borderline personality difficulties.