The couple, who first met in June in London's Punk nightclub, apparently parted ways because Deyn did not want to continue a long distance relationship.
"Miles has taken it badly. Agyness tried to let him down as gently as she could," the Sun quoted a source as saying.
The insider added: "She explained that she didn't want to carry on seeing him because she couldn't devote enough time to him. She said that her modelling career had to come first at the moment and it wasn't fair to Miles for him to be a poor second.
"With Aggy often in the States and Miles working in England, trying to keep a transatlantic relationship alive was difficult at the best of times. Aggy is constantly rushed off her feet so she had to end it before it got too serious."
However, Miles joined a league of celebrities at the launch of The Dirty Mac club night in Soho recently, where he got drunk and flirted with women.
The source added: "Miles has been feeling really low, but a night out with friendly faces helped him. He sank a fair few jars and did an impressive amount of flirting and was pretty steaming by the end."