The couple, who met on Twitter -- she followed him first -- got engaged in October, only six months after making their public debut as a couple at the premiere of the movie "42."
Big Sean's rep said in a statement obtained by Us Weekly that the 26-year-old rapper was the one to call things off. A source told the magazine yes, that's how things went down.
"The recent rumors and accusations reported by so-called or fake sources are simply untrue," the rep added. "Sean wishes Naya nothing but the best and it is still his hope that they can continue to work through their issues privately."
Those "recent rumors" alleged that the rapper, real name Sean Anderson, had cheated on Rivera, 27, and then confessed to her about it. Sources told TMZ that the rumors were false, but instead alleged that a too-controlling Rivera was jealous of women her former fiance worked with and met while touring.
The actress and singer was not wearing her engagement ring Tuesday night at the Marie Claire Fresh Faces event in L.A., E! News noted.
However, just last Friday Rivera was tweeting thanks to Cosmopolitan for featuring her and her beau in its list of the 19 cutest engaged celebrity couples.
She'd gushed even more in January talking to Cosmo for Latinas, saying of Big Sean, "I think he’s going to be an amazing husband, and he’ll make a great father someday.
"He’s so kind to people, but he also wears the pants in our relationship, which I love. We Latinas are very independent and strong, so it’s even sweeter that I’ve found somebody who can let me out of that role for a minute."