A Leeds Crown Court judge handed Craig Hope an extended prison sentence totalling 14-years after hearing the robbery had a lasting impact on his victims.
Hope was wearing a skull mask when he barged into the kitchen of the woman's home in Armley and knocked her to the floor while her 12-year-old son and daughter aged three were in the house.
Leeds Crown Court heard Hope threatened the woman with the knife as he demanded money.
Prosecutor, Howard Shaw said the woman let her Akita dog out of its cage and Hope kicked it before pulling the woman's top over her head and searching her bra for money.
There was a struggle and the dog bit Hope, who stabbed it in the neck and leg before grabbing the woman's purse and fleeing the scene.
The court heard the dog also bit the woman during the incident, which happened just after 2.30pm on August 21 2019.
Mr Shaw said the woman's 12-year-old son witnessed Hope threatening his mother with the knife.
A woman who was passing by saw Hope leave the house and followed him and took photographs of him.
The photographs led to Hope being identified in connection with the robbery.
Mr Shaw said, after he was arrested, Hope told police he knew the victim.
Mr Shaw said: "He claimed to be having a secret affair with her."
Mr Shaw added: "That was a complete fabrication, the complainant had never seen the defendant before."
The court heard the woman wrote in a victim statement: "I thought I would be killed, stabbed to death by a drug addict who was hugely out of control."
The woman's son wrote in a victim statement: "It was the most scary thing I can possibly imagine. Nothing comes close, I thought my mum could have been killed."
Hope, of no fixed abode, admitted robbery.
Hope has 21 previous convictions for 56 offences including robbery, assaulting a police officer, grievous bodily harm with intent and affray.
Allan Armbrister, mitigating, said Hope started sniffing glue as a 12-year-old schoolboy and became involved in criminality at a young age.
Judge Simon Phillips QC handed Hope an extended sentence totalling 14 years - a nine year custodial term followed by an extended five year period on licence.
Judge Phillips told him: "Her young son heard her scream. He came downstairs to see you with a knife at her neck, He could see his mother was terrified."