TMZ reports that Mariah Carey and Nick Cannon, celebrity couple seen often on event red carpets, have been separated and working with a divorce lawyer for months. The divorce, TMZ alleges, is "a done deal."

The pair have reportedly been living apart since May, seeing each other only when Cannon drops by to visit the kids. How could this have happened to a couple that seemed so in love? TMZ's sources have an idea:

Our sources say ... Nick's appearance on Big Boy's radio show in March was the beginning of the end. Nick played Big Boy's game — name the 5 celebs you've slept with. Nick named 5, but our sources say the one that made Mariah insane was Kim Kardashian.

Oh shit. TMZ says Mariah felt humiliated and the relationship never recovered, adding that she was also upset at Nick's tendency to take "every gig that's on the table," leaving him little time to be with their kids. Of course, there are two reportedly two sides to the story:

For Nick's part … we're told he feels Mariah has become impossible because she surrounds herself with "yes men." He says she can't handle it when he dares to disagree with her. We're also told Nick is incredulous Mariah is bitching about his work ethic … he says he's generated $75 million since 2011 for the family.

Our deepest regrets to the unhappy couple.

[image via Getty]