The pregnant model has released a statement following a flurry of emotional tweets earlier in the day which saw her accusing Kieran of infidelity and branding him "disgusting".
Businesswoman Katie claimed Kieran had been sleeping with a friend of hers for seven months - despite the fact she and Kieran are new parents with a second child on the way.
Confirming the split in a statement, she said: "I appreciate most people will have seen my tweets on the subject of my marriage to Kieran.
"I make no apologies for them though it will be appreciated that, sending them immediately after Kieran confirmed to me what he had been doing for the last 7 months, those tweets were a sign of my heart breaking."
She added: "That he was doing it with a close friend of nearly 20 years is hard to understand."
The emotional tweets had read of the alleged other woman: "She is a wh*re, home wrecker sl*t... Kieran is a disgusting human being doing this after I've just had a baby and still doing it till I caught them.
"No human being deserves this especially being 6 months pregnant."
Katie then added: "Worse pain in the world."
Katie's shocking split came just three days after she happily confirmed she is pregnant with her and Kieran's second child. They are already parents to Jett, who turns one this summer.
The star went on to say that in contrast to her emotional tweets, her statement is from her head, not her heart, saying: "I am appalled that someone I loved, trusted and believed in has behaved in this way.
"If he had so little respect for our relationship I would have hoped he would have thought about our child or the one that we have on the way.
"That he did not means he will no longer be part of my life. I will do all I can to ensure he maintains a relationship with his children should he want that."
Katie concluded her statement by saying: "I am so grateful for the love of my children and family at this time."
Kieran has yet to publicly address the cheating accusations or the separation.
Katie and Kieran married in the Bahamas in January 2013 following a whirlwind romance and Christmas proposal. They welcomed their son Jett that summer and, just three days ago, confirmed they are expecting baby number two, making Katie's divorce news all the more shocking to some.
Less than a month ago, they had seemed blissfully happy while enjoying their first sunshine holiday as a family, sharing pictures of themselves kissing on the beach in Cape Verde and showing off their wedding rings.
Katie is also mum to children Harvey, Junior and Princess from previous relationships.
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Katie Price's past boyfriends in pictures:
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