The model, 36, was furious and heartbroken last month when she discovered Kieran had been sleeping with her close friend Jane Pountney for seven months.
Katie was particularly shocked as she's around six months pregnant with Kieran's second child. She accused him of starting up the affair shortly after the birth of their first son, Jett, last year.
Since then, we've heard various tidbits about the affair - Kieran claiming he's got compulsive addiction, Jane's husband saying she was falling in love with Kieran etc - but, according to Katie, none of it compares to the truth.
"You've only heard bits, but if you heard the whole truth you'd be like, 'Jesus'," she told The Mirror.
"Trust me, if everybody knew what was going on they'd be like, 'How the hell is she sitting here today?', because it's that bad."
In another interview with The Sun, she claimed there were "hundreds" more allegations just waiting to come out.
Katie made the comments at her first public appearance since the affair news broke. She was at a photocall for ColourB4 hair colourant removal, which she is an ambassador for.
And in true Pricey style she didn't shy away, rocking up in an insanely colourful rainbow-inspired outfit, complete with multi-coloured hair and boxes of colourant woven into a tiara.
Despite her bold return to the public eye, she admitted she's still dealing with her heartbreak.
"There's lots more I want to say but I have to be grown up about it," she told The Mirror. "It's raw. The word 'friend' is sensitive at the moment. But my life has ups and downs and ups and downs. I'm like a yo-yo."
Katie made her husband's betrayal public on 7 May with a flurry of tweets branding him "disgusting" and calling former friend Jane a "wh*re" and a "homewrecker".
Jane had been one of the few guests at Katie and Kieran's wedding in the Bahamas in January 2013.
It's been claimed that Katie was already suspicious of Kieran and Jane's relationship after catching them embracing while on a group holiday earlier this year, but at the time, Kieran insisted it was just a drunken kiss.
We've also learned that Katie's younger sister Sophie was the first to raise the alarm.
Since the affair was confirmed, Jane has remained out of the public eye, only saying that she deeply regrets what happened. Her husband Derrick, however, recently said the couple are divorcing and suggested Jane had been falling in love with Kieran.
Kieran, however, has disputed this, insisting in a recent interview that his time with Jane was nothing but "sleazy, dirty sex" and saying he has compulsive addiction, which he's now seeking treatment for.
He has been vocal in his desire to win Katie back but, so far, she isn't responding.
The former couple did meet up at the weekend to attend a hospital check-up on their unborn child, but friends of Katie said it shouldn't be taken as a sign she's forgiven him and wants to reunite.
Katie has, however, apparently told pals she wants Kieran there at the birth as it's his child too.
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Katie Price's crazy costumes in pictures: