Vanity Fair said the 21-year-old has been dating Italian model Giada Gianni, who is also 21, since 2015.
"Charles left me," she is quoted as saying to the fashion magazine.
"He wants to devote himself only to Ferrari", she told Vanity Fair.
The Monaco-born driver is currently third in the drivers' standings with five-time world champion Lewis Hamilton likely to claim the 2019 title with relative ease.
Leclerc won two consecutive races at Spa-Francorchamps in Belgium and Monza in Italy this season but has been caught up in a frosty relationship with team mate Sebastian Vettel.