The Manchester City hot shot, 29, who broke a rib in the smash, is said to have drifted apart from 31-year-old Karina Tejeda.
Karina, known as The Little Princess in their Argentinian homeland, and Aguero had been dating for four years.
But she was reportedly angry at him for attending a party with several models on a brief return to Argentina.
The hitman is said to have gone along with team-mates from the national side ahead of an international match.
It comes after £50million Aguero was hurt in Amsterdam on Thursday when his taxi skidded and hit a lamp-post.
Karina only learned of the smash from an Argentinian TV reporter.
She appeared blasé when told, shrugging her shoulders as she said: “Really? I didn’t know. Oh well.”
Last week, she spoke about the couple’s break up while appearing on a cookery TV show in Argentina.
Asked about the separation, she replied: “From the start I didn’t say many things. And I feel really good for having done it that way.
“Today I don’t want to tell anything. I simply realise that people expect that I should sit down to maybe speak badly or drop a hint in one of my songs.”