Although the 39-year-old reality TV star had vowed to keep their marriage split amicable - after Kieran cheated on her with their children's nanny - Katie asked him to leave their home after he refused to accept that their relationship was over.
A source told The Sun: ''It's pretty unbelievable but Kieran actually believed he could cling on to their marriage after all he's done -- and that has really annoyed her.
''Katie is heartbroken by yet another betrayal yet he still didn't seem to get the message it was over.
''He was hanging around this weekend like everything was fine, having been told repeatedly it was finished.
''He was even posting things on social media in a bid to make everything seem normal between them.
''That couldn't have been further from the truth and sparked a new argument. Behind closed doors all hell was breaking loose, she was absolutely raging. Eventually he gave up and left.''
The 'Loose Women' panellist - who has children Harvey, 15, from a previous relationship, Junior, 12, and Princess, 10, with her ex-husband Peter Andre, as well as Jett, three, and two-year-old Bunny with Kieran, 30 - had previously forgiven Kieran after he had cheated on her with her best friend back in 2014, but she has now insisted that he has had his last chance.
Speaking previously about her decision to call time on their four-year relationship, she said: ''I was gutted. For a year I was basically paying her to f*** my husband. Kieran told me they were f***ing all over my house for a year.
''They had sex everywhere except in our bedroom, they even did it in the kids' bathroom. When I confronted him he denied it at first, even when I said she'd admitted it. I was crying, asking, 'How could you do this to me again?''
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