Jenny Cupit, 25, from Warrington, sobbed uncontrollably in the dock at Chester Crown Court as the judge told her she was a serial liar who would be behind bars for a long time.
Cupit had denied murdering Kathryn Linaker, 33, but admitted manslaughter on the grounds of diminished responsibility. Yesterday, she changed her plea at the eleventh hour and admitted murdering the primary school teacher and mother of two on 17 April last year.
Mr Justice Sachs said: "What you did on that day was an absolute outrage. You killed that woman out of lust for her husband and jealousy for her.
He said he had listened to the mitigation and, "it's not that great... Nobody hearing the evidence in this case can fail to feel anything but revulsion."
During the five-day trial, the court heard how Mrs Linakerwas bludgeoned and stabbed to death in front of her four-month-old daughter. She did not know her husband, Chris, was having an affair, but had warned him, a week before her death, that Cupit was interested in him and could be a threat to their marriage.
Cupit, a mother of two, and her husband, Nick, met the Linakers at the Warrington-based Centenary Operatic and Dramatic Society. The affair between Cupit and Mr Linaker, 35, began in January 1997. They met at least once a week for sex and talked regularly by phone. Their affair continued for 16 months.
Mr Linaker wrote one letter to Cupit, who was pleading to elope to Canada, saying: "We have shared almost every sexual experience together and I can't imagine life without you."
But Cupit knew that Mr Linaker still loved his wife. She visited the Linaker's home armed with a small knife and plunged the knife into Mrs Linaker's back with such force that the blade snapped. She then stabbed her in the stomach with a larger knife taken from a kitchen drawer.
First she told police of a "mystery skinhead" who forced his way into the house and attacked Mrs Linaker. When she was arrested, she gave a dramatic account of how she had killed Mrs Linaker after the affair was discovered, and claimed that Mrs Linaker had attacked her because she was jealous of her popularity. Her claims were never believed.
Mr Linaker left the court with his head down yesterday and refused to comment. During the trial he sat grim faced at the back of the public gallery as Adrian Fulford, QC, defending, said Cupit was mentally unstable and Mr Linaker had to take responsibility for what had happened.Reuse content