Eminem's uncle Todd Nelson has told Sky One (The Real Slim Shady documentary) that Eminem often got a thrill when bisexual Kim brought girls home after nights out and that the three of them would go at it.
Todd said: "Kim has a sexual hold on him because of her bisexuality. She brings women home and puts them in bed with her, and when Marshall comes in he doesn't come home to just Kim - he comes home to whatever's in bed. Why would you not want a wife that has other women waiting for you? It's every man's dream, right?"
Eminem is applying for custody of daughter Hailie, seven, after Kim was arrested on cocaine charges.
The Real Slim Shady is on Sky One on Sunday at 9pm.