The 20-year-old, who had a rollercoaster romance with Bieber which lasted about two years, is now setting her eyes on an older man, reported the Sun online.
"Selena is looking to date an older man this time. She finally realised how toxic it was to date a toddler like Justin," the source said.
"Selena is doing really well and feels like a weight has been lifted off her shoulders now that Justin is out of the picture."
Earlier this week Bieber angered fans by turning up two hours late for a concert in London.
Since heading to the UK for his 'Believe' tour, Bieber has regularly made headlines for some of his demands and behaviour including wearing a gas mask on a shopping trip in the capital.