A source told People magazine: 'First the split didn't seem to faze Mariah. It was like she expected things to be fine soon. Now she realises that things aren't fine and not being with James makes her depressed.'
Insiders says Mariah - who has five-year-old twins, Morrocan and Monroe, with ex-husband Nick Cannon - has been going out to take her mind off things.
The source continued: 'She doesn't want to sit at home and dwell on it. She is very hurt that he dumped her. She knows she will never be able to find someone like him.'
It was recently claimed that Mariah had begged ex Nick for a divorce so she could marry James
The former couple split in August 2014 but their divorce had dragged on because of legal wranglings about the children.