Natasha Gordon, 49, “changed her mind” after agreeing to take her own life alongside Matthew Birkinshaw in 2015.
The ex-model left him in his car at a reservoir in Rutland, East Midlands, where he was later found dead.
Cops were called to her home in January this year after her partner grew concerned as he had not heard from her for over a week.
The inquest into her death at Cambridge Coroner’s Court heard that she had made previous attempts on her life and was dealing with a range of mental and physical health issues.
In 2017, she had been diagnosed with “emotionally unstable personality disorder” and shown signs of PTSD, the court was told.
A visit to a GP for “abdominal issues” in 2022 also saw her “suicidal ideations” noticed by doctors.
Coroner Simon Milburn noted that she had declined mental health assistance despite her severe illness.
He ruled her death a suicide due to “fatal pressure” on her neck, adding that she had been “dead for some time” by the date she was found.
Ms Gordan spent four years behind bars after being sentenced in 2018 for her part in Mr Birkinshaw’s death.
She was described during the trial as an “enthusiastic advocate” of suicide, with texts showing her encouraging the 31-year-old to take his own life.
Cops also discovered messages in which she tried to set up similar arrangements with others.
Mr Birkinshaw’s mother Margaret said in a victim impact statement: “It’s impossible to put into words the effect the loss of Matthew has had on our family.
“He was everything to us and has left a space no-one else can ever fill.
“His last words to me were ‘Give me a hug mum, I’ll be back tomorrow.’
“I’ve asked myself a million times over the past two years ‘Why didn’t I ring him? Would it have made a difference if he’d heard my voice?'”
If you are affected by any of the issues raised in this article, please call the Samaritans for free on 116123.