Sarah Lorking, 36, was told by the judge that she had “come within inches of going inside” after she started a secret relationship with Bulent Sessacar, 36.
Lorking walked free from court after she was handed an 18-month jail sentence, suspended for two years.
Sessacar was serving a minimum 10-year eight-month life sentence after he stabbed his wife Rebecca Sessacar, aged 25, 58 times in front of a six-year-old child in Croydon, south London, in December 2012.
Lorking, of Northampton Road, Market Harborough, was secretly planning to start a new life with the killer when he was set to be released from jail next year.
But prison authorities were tipped off about their relationship.
And Sessacar was moved out to another high-security jail, Leicester Crown Court heard last Friday (May 20).
He killed himself just days later.
And Lorking admitted an offence of misconduct in a public office after she was arrested as a full investigation was launched.
Sessacar was jailed at London’s Old Bailey court in 2014.
The personal trainer admitted manslaughter by diminished responsibility after knifing his wife repeatedly due to a cocaine and steroid-induced psychosis and a borderline personality disorder.
Sessacar was branded a "dangerous" criminal by the judge who locked him up.
Paul Prior, prosecuting, told Leicester Crown Court that Lorking was in a live-in relationship with a fellow prison guard when she fell for the killer.
Sessacar's cell was searched on January 12 last year and a number of cards and letters were seized.
They showed that he was having an affair with the anonymous sender, the court heard.
Mr Prior said that Lorking knew that it was forbidden after she was given "words of advice in that regard" two years earlier.
But she denied being in a relationship or sending cards or letters to Sessacar when quizzed by the prison governor.
Lorking had lobbied the prison psychiatrist in late 2020 to be made Sessacar's key worker and he also made a similar request, the court was told.
She was said to be aware of his ongoing mental health issues.
Sessacar was then transferred to Woodhill Prison at Milton Keynes.
And he took his own life on January 21, 2021.
Mr Prior said Lorking later admitted to a colleague she had formed a “relationship of sorts,” saying it amounted to kissing, as she confessed her heartbreak at his death.
Mr Prior said: “They had made plans to live together after his release in 2023.”
Lorking's ex-partner gave a statement to the court saying that she admitted to him that she loved Sessacar.
An anonymous letter, from 2020, found in Sessacar’s cell, referred to the sender being “horny” for him and said that there were “two Christmases to go”.
Mr Prior said: "Mr Sessacar formed a bond with the defendant, which was torn away when they were discovered - and he suffered in respect of that.
“There's no suggestion that her attention was unwelcome.
“It's not suggested he pursued her for nefarious purposes, such as bringing in drugs or mobile phones.”
Michael Garvey, defending Lorking, said: "She was in close contact, as his key worker, when her relationship at home wasn't a good one.
“She allowed herself to lose sight of her professional obligations and over-stepped the mark to send those cards and talk to him in the way we can see on the exhibits (cards and letter) produced in court.
"There are many people and her family who support her and view her in a positive light."
Mr Garvey said Lorking, who’s now jobless, is now "happily with a new partner”.
"Consider how harsh an immediate sentence would be,” he said.
“If she was in custody, almost certainly, she'd serve it in solitary confinement or if sent to an open prison she'd be at risk."
Recorder Adrian Reynolds told Lorking: "I've found this case very difficult.
“This doesn't have the features of any additional offences such as bringing into prison mobile phones or drugs - but it doesn't have the mitigation of you being manipulated by a predatory inmate.
"You were in a powerful position, of a man with mental health difficulties.
“You abused your authority and employment and that troubles me considerably.
"I accept things were difficult for you at the time, with issues in your life,” said Recorder Reynolds.
"I don't doubt there are prospects of rehabilitation.
“Can I justify suspending the inevitable custodial sentence?"
Moments later, he told Lorking as she gasped in relief: "Well I am going to suspend the sentence."
But Recorder Reynolds warned her: "Don't be under any illusions, you've come within inches of going inside.
“You need to grow up, you cannot play with people's emotions.
“I don't think you really appreciate how serious your behaviour was.
"I am making a 27-day rehabilitation activity requirement, designed to help you with your thinking skills that were noticeably lacking during this period of offending,” added the judge.
As she left the dock to leave the court, Recorder Reynolds told her: "You are a very lucky woman Miss Lorking."