The X Factor host, 31, is said to be 'devastated' following the sad split.
The Sun on Sunday reports that their three year relationship ended abruptly last week after a holiday together.
According to the newspaper, his busy work schedule and the stresses of filming The X Factor and juggling his singing career were partly to blame.
A source said Olly was 'heartbroken', adding: "The split has just happened and it is very raw for Olly, he still feels numb.
"He always worried that his relationship would struggle because he'd always put his career first.
"Now, with X Factor and his singing on the go, that's exactly what has happened."
The insider continued: "They worked so hard to keep their relationship strong, all their friends are stunned they couldn't make it work.
"Olly has kept himself busy with work to distract himself and took himself on a lads night out to see One Direction.
"But he looked upset during the gig, like his mind was elsewhere."
Following the story, a fan said: "Shame, but then again there will always be someone just waiting to pick up the pieces."
Another said: "Yep, you make your choice, fame or another normal life. Hope you make the right one Olly, just be sure you're okay."
Earlier this year, Olly hinted that his song 'Beautiful To Me' was written about commercial property manager Francesca, 26.
In a very recent interview, Olly confessed that Francesca missed his belly after the star lost weight and gained a six pack.
He told Fabulous magazine: "She misses the comfort belly, something to snuggle up to! I always joke around with my girlfriend and say she's a bit of a feeder. She has a go at me for saying that, though. But we were sitting there just eating all the time – chocolate, crisps… Just being in a relationship made me put on a bit of weight!"
The singer also told the magazine that Francesca has no interest in fame, preferring to stay out the limelight.
He said: "We try to keep things private so Francesca can have a normal life. That's why I like her and find her attractive. I don't want her to be plastered in newspapers and everyone to know what we're up to."
Olly was a runner-up on The X Factor in 2009 and has gone on to have a fantastic career despite not winning.
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