The mum-of-four only announced she was pregnant with her fifth child - her second with her stripper and builder husband - earlier this week.
Katie Price and Kieran Hayler
But in a series of messages she posted online, the 35-year-old model told her fans: "Sorry to say me and kieran are divorcing."
Airing her upset to the world via Twitter, she wrote: "No human being deserves this especially being 6 months pregnant."
Another message added: "Worse pain in the world."
A spokeswoman for Price did not wish to comment when asked about the messages posted on Price's account, which also made allegations about the reasons for the breakdown of her marriage.
It is the latest chapter in the colourful world of Katie who has previously been married to singer and TV personality Peter Andre and the 'Celebrity Big Brother' contestant and cage-fighter Alex Reid.
She and Reid separated in January 2011 after being married for less than a year.
She and Hayler had their first child together, Jett, in August last year.
She also has two other children, Junior and Princess, from her four-year marriage to Andre and a son Harvey from her brief relationship with footballer Dwight Yorke.
In a magazine interview this week she had told how she learned she was expecting on returning from a holiday in Cape Verde.
She told Now magazine that they thought she was just a few weeks pregnant when the couple went for a scan the following day.
"We were lying there... then this picture flashed up on the screen and we saw this enormous baby," she said.
"I was in shock, he was in shock - even the doctor was in shock. I was still in size 6-8 trousers… None of us could actually believe it."