The on-again off-again couple, who officially went public in August last year, following Jenner's 18th birthday party, reportedly started dating in July 2014.
On Friday (local time), Us Weekly reported that 23-year-old Brazilian model Annalu Cardoso "confirmed" rumours of an affair with the rapper during the time he was in a relationship with Jenner.
Cardoso claims the pair started their relationship in December of 2014. According to Us Weekly, a source confirmed: "Tyga is very careful and waits until Kylie is out of the country (to meet up with Cardoso)."
Neither reps for Jenner or Tyga have confirmed the cheating allegations.