The glamour model has branded her cage fighting spouse of 11 months a "fame hungry sponger" and reportedly banished him to a dressing room in her mansion in Surrey, Southern England.
Katie, 32, reportedly told friends: "I need him out of my house, and I need him out of my life for good. I convinced myself that I was in love with him, but looking back I probably wasn`t."
Katie has made it clear her marriage is over and reportedly prepared a statement, but withheld it after Alex, 35, begged her for more time to discuss their relationship and come to terms with the split.
A friend close to Katie told the News Of The World newspaper she had said: "It`s over. There is no way we are going to work this out. I want Alex to leave this relationship with a scrap of self-respect."
The model married Alex in Las Vegas in February 2010, but said he has since become obsessed with fame, and compared him to first husband, singer Peter Andre, whom she divorced in 2009.
Katie reportedly told friends: "I thought Alex was an easy-going athlete who had no interest in showbiz, fame or wanting a TV career like Pete.
"He was just the opposite of all that, just an ordinary bloke. I loved the fact he wasn`t in my world. But as soon as he got to my world, he wanted to be in it himself.
`He wanted to become a TV personality like me, a magazine columnist like me and advertise clothes like me. I hated that."
Alex - who married Katie without a pre-nuptial agreement - is reportedly asking for £1million for their split, though Katie is thought to have agreed to pay him only £250,000, the figure she believes he has earned during their marriage.