The 34-year-old and Ianthe, 23, got together in February this year, before breaking up in May.
Calum and Ianthe reconciled shortly afterwards but sources have claimed it’s over again.
The Sun reports that Ianthe flipped when she caught former lothario Calum in a hotel room with other women.
An insider told the newspaper: “Ianthe dumped Calum when she found him drunk in a hotel room with a load of pals.
"It was the final straw as she’s not prepared to be with anyone who won’t compromise."
“He promised he’d change but he’s too selfish," they added.
"She can’t stand him anymore. She tried to see if he would change after they split but he’s shown his true colours.”
According to the source, Calum tried to convince her that the party was innocent but she wasn’t having it.
Earlier this year Calum admitted that Ianthe is the only woman he’s ever introduced to his mum Angie.
He told Hello! magazine: “I’ve kept a lot private, not wanting to let people get too close.
“But they get on so great. My mum can see how crazy I am about Ianthe, and she’s thrilled that she’s come into my life.”