Evans said she was "frustrated" by his behaviour and emotionally hurt by Tostee, who she described as being "obsessed" with his "old life" which revolved around partying, drinking and girls.
"He wants to live like that forever," she said.
Evans was initially attracted to his quick wit and thinking, debating skills, occasionally chatty and outgoing nature and similar hobbies.
But said he was set in his ways, unmotivated, scared of change and unwilling to compromise: "It was either his way or no way," she said.
The pair were together for about a year, described as "an intense time with a lot of emotions obviously".
Gable Tostee was exonerated of the murder of Warriena Wright by a jury in October. Photo / Supplied
Daily Mail Australia first revealed Evans' role supporting Tostee throughout the ordeal of the nearly fortnight-long murder trial.
"We had hoped to begin a new chapter of life but he became resistant," she said.
"I just had no more to give in the end but he seems (unfazed) as to be expected I suppose."
She declined to go into the specific circumstances of their break-up - except to say it was not related to the trial - but rather his personal behaviour. She also described his supportive parents as "incredible" people.
Tostee's trial received international attention - with news anchors broadcasting live from the grounds outside the Brisbane courtroom - because of the involvement of the popular dating app.
His Tinder date, New Zealand woman Warriena Wright, plunged from Tostee's 14th floor Surfers Paradise apartment to her death on August 8, 2014.
Lizzi Evans said she was "frustrated" by the 30-year-old Gold Coast playboy's behaviour. Photo / Facebook
Tostee - who regularly picked up women on Tinder and boasted of bedding more than 200 women in his lifetime - was found not to have culpability for Wright's death by a unanimous jury verdict.
Since the trial, Tostee has answered questions from TV news magazine programme 60 Minutes and members of a Facebook discussion group.
"I suffer brain damage every time I read a dumb comment," he told punters last week.
