The 40-year-old former glamour model recently split from Kris Boyson and the fitness trainer believes she is scarred by her past relationships, in particular her first marriage to the 'Behind Closed Doors' hitmaker, which ended after three years in 2009.
Kris said: ''She had such a hard time after Pete, I reckon she has really struggled from that.
''I think that was really mentally hard for her and I think that damaged her the most.''
Kris began dating Katie after her marriage to Kieran Hayler fell apart and he admitted he did as much as he could not to ''worry'' her and even missed his best friend's stag party in an attempt to stop her getting hurt.
He told the Daily Mirror newspaper: ''Since the day I met her I have not followed one person on Instagram so she didn't have to worry and even in the early days, I was meant to go on my best friend's stag do, but I didn't even want to go because I knew it would worry her.
''I know how hurt she has been before and I never wanted to put her in that position where she worried.''
Kris claimed Katie - who has Harvey, 16, with former boyfriend Dwight Yorke, Junior, 13, and Princess,11, with Peter and Jett, five, and four-year-old Bunny with Kieran - has few real friends and doesn't trust many people.
He said: ''She has a lot of famous friends but her close friends aren't famous.
''She likes to keep herself to herself. But then when she goes out she likes to talk to everyone.
''Her and Kerry Katona talk all the time, but they never see each other.
''At one party Kerry came up to me and was like 'I've heard all about you.''
''But she hasn't got many real friends, her social circle is so small, she can't trust anyone. She is quite paranoid, and I don't blame her. Everyone slates her.''