Terri-Marie Palmer, 23, plunged a kitchen knife into Damon Searson’s chest after setting up home with him in an attempt to distance him from a life of drink and drugs.
Sentencing Palmer to a minimum term of 12 years, Mr Justice Kerr said: “You took his life yet you loved him.
“You have taken him from his family forever.
“Your relationship with Damon was destructive. You meant to help him overcome his demons, drink and drugs. You tried to help him become a better person and make something of his life. You wanted both of you to be happy.”
Palmer, who has worked as a hairdresser since the age of 14, met Mr Searson while he was in rehabilitation in Lancaster after being released from a prison sentence.
Damon and his roommate Andrew Lynch would visit the Costa Del Sol barbers, where Palmer worked, to have their hair cut and before long a friendship formed between the three.
But last February, Palmer and Searson began what was to become a tempestous and destructive romance.
As she gave her evidence from the witness box at Preston Crown Court, Palmer told the jury her lover would be jealous and controlling.
After leaving rehab he spent his time between Heysham and Liverpool - where he would fall back in with his old crowd and self-destructive ways.
Mr Lynch told the court Damon would ask him to walk past Palmer’s workplace to check she was where she said she was.
Meanwhile in Liverpool he would go “off the radar” spending Palmer’s money on drink, drugs and other women, the court heard.
In the weeks leading up to Searson’s murder, Palmer started working overtime to save up for the caravan for them at Stud Farm Park, Oxcliffe Road, Heysham.
But on August 13 she complained to a friend he had spent his money on a phone and shopping and once again she was left to pay the rent.
She told her friend: ““He p***es me off sitting on Facebook, completely blanking me when I’m talking to him. All he does is sits there and adds loads of girls. He’s a f***ing little prick.”
By midnight, she had decided she was going to leave her partner.
At 1.30am he was pronounced dead.
Palmer picked up a kitchen knife they had bought that day and stabbed Mr Searson through his heart.
Mr Justice Kerr said: “The crime was completely unpremeditated and you regretted it immediately. I accept you were as horrified as everyone else by what had happened.
“You did not intend to kill him. You did however intend to do him really serious harm.
“Many murders are committed by far worse people than you. Until this happened, no-one would have thought of you as an evil person.
“Yet what you did to Damon Searson was evil, during that one terrible moment in an otherwise blameless and productive life and you must answer to the law for it.”
Palmer, of Warton Avenue, Heysham, maintained throughout the trial she had not stabbed her boyfriend, telling the jury she had thrown the knife to him so he could mend his mobile phone.
In an earlier account she told police officers Mr Searson had stabbed himself as he was playing with the knife, and during interview said they had been playfighting.
When she was told her boyfriend had died, Palmer broke down and said: “I didn’t mean for it to get him.”
However the jury convicted her of murder.
Det Insp Nina Foley from Lancashire Constabulary’s Force Major Investigation Team (FMIT) said, “This was a tragic case where a young man received a single stab wound to his chest during a domestic dispute with his girlfriend. Unfortunately, despite the best efforts of police officers and paramedics, the injury proved fatal.
“Palmer had attacked Damon Searson following an argument that night, giving different accounts to the ambulance service and attending police officers. She went on to give a further different versions during interview and her trial this week.
“The events of that night have had far reaching consequences and two families have been left devastated. Sadly, Damon Searson lost his life but Terri Palmer will have to live with the knowledge that she was the one responsible.”