Neither Sainz nor Ferrari team-mate Charles Leclerc have felt comfortable with the SF-23 this season, and upgrades brought to the Spanish Grand Prix only seemed to take the team backwards.
Speaking with the fans at the Spanish Grand Prix, Sainz said: “When I’m at home I take time to spend with my family, my dog, my girlfriend if I have one."
His uncertainty appears to have materialised, as revealed by Hernaez.
Sainz's heartbreak
The model confirmed the split in an interview with Hola Magazine.
Hernaez had some short comments to make about the break-up, but wished Sainz well, stating: "I'll keep the good always, of course. And I wish him all the happiness."
Sainz could only manage a P5 finish after starting on the front row in Spain
Hernaez and Sainz had been dating since 2016, but the 28-year-old model hadn't been at a grand prix since the season opener in Bahrain.
The motivation for the split has not yet been confirmed by either party.