Stacey Flounders, 29, appeared by the disgraced footballer’s side at Bradford Crown Court in February and March 2016.
But the court later heard the couple — who had recently welcomed a baby daughter — had split.
Johnson, 31, is now due out on licence having served half his six-year sentence for grooming and sexual activity with an underage fan.
Stacey took their daughter Ayla to visit him in Moorland prison on for the youngster’s fourth birthday last month.
“It’s been three years, and she knew this day was going to come”
According to the Daily Mirror, she told pals: “He is her dad, so I will keep up the relationship for her.”
But she reportedly added: “We won’t be getting back together.”
The mum is reportedly anxious about the day she has to tell their daughter about Johnson’s crimes.
A source said: “That will always be on her mind.
“That has to come some day, and you have to think about how you get that in first.”
She is also reportedly worrying about any backlash against her when Johnson is released.
The source added: “It’s been three years, and she knew this day was going to come.”
The former air hostess met Johnson in 2011, when he was playing for Manchester City.
She moved into his luxury mansion in 2013 and had his baby in 2015.
But their relationship was rocky, due to Johnson’s infidelity.
Johnson told police after his arrest: “We have had a few arguments in the past about me texting other girls.”
He added: “I have a girlfriend and family. I said to myself, ‘It’s poor like, I should have known better’.”