The model is said to have called it quits on their relationship, after hearing rumors about the R&B singer and ex-girlfriend Rihanna.
Tran is said to have ended the couple's romance after Brown was reportedly spotted kissing Rihanna at New York nightclub Griffin on Monday night (October 1).
"Karreuche finally had enough and dumped Chris for good," a source told RadarOnline.
"Karreuche and Chris had been on thin ice for a while, but after he was spotted getting with Nicole Scherzinger in a Los Angeles nightclub recently, and then when reports surfaced that he had hooked up with Rihanna... she finally dumped him.
"Karreuche was very patient with Chris, and never nagged him about what he had been doing whenever they were apart. She never went through his cell phone, but she suspected for a long time that he had been cheating on her for some time, she just never had the proof."
The couple have been dating since late 2011, but Brown's continued close friendship with Rihanna was apparently a source of tension and Tran is said to be fed up of being embarrassed by his actions.
"They are both young, but she just couldn't tolerate being publicly humiliated anymore," the insider further claimed. "The relationship was tumultuous and filled with drama, and she just had enough, and wants a healthy relationship."
Scherzinger and Brown recently denied reports that they had been seen kissing, with the X Factor judge's publicist saying that photographs of the pair merely showed "two old friends who were trying to talk at a very loud club".