New details have emerged about the surprise split between rapper Big Sean and Naya Rivera. It is now rumored that he cheated on her with one of her co-stars. The young couple began dating last year, but Big Sean ended the relationship last week, just months after their engagement.

“After careful thought and much consideration, Sean has made the difficult decision to call the wedding off,” the rapper’s rep tells Us. “The recent rumors and accusations reported by so called or fake sources are simply untrue. Sean wishes Naya nothing but the best and it is still his hope that they can continue to work through their issues privately. We will not be commenting again on this matter." Big Sean is rumored to have cheated on her, and Star magazine claims he admitted to it, though his rep says that is untrue.

However, Blind Gossip, which posts entertainment news rumors without specifying the people involved, wrote about Big Sean and Rivera, or so it seems. “It is hurtful when your fiancé cheats on you. It is even more hurtful when it’s with someone you know,” the site says.

“This pretty television actress found hookup text messages between her Fiance…and one of her television colleagues!

She screamed at the fiancé about why – of all the people in the world – why would he f-ck around with one of her colleagues? The fiance couldn’t even deny it. The evidence was right there on his phone.”

Most commenters believed the story was about Rivera and her “Glee” co-star Lea Michele.

Now, TMZ is reporting that Rivera and Michele had a big fight on set recently. Though it seems to have been about Michele’s “diva antics,” that could be a cover for the real issue.