Rap music producer Omar "Iceman" Sharif, who is a friend of Kevin's, tells In Touch, "Britney was into threesomes and girls."

He says Spears would often invite a bunch of girlfriends over to the couple's house to party.

An insider adds, "Britney would often disappear into a bedroom with her girlfriends.

Sometimes it was three girls, and sometimes there were more like six," the insider says.

"I heard about her being with girls at least 20 times while they were married."

A friend tells In Touch that Kevin plans to use tales of Spears' secret sexual exploits and drug use in his battle for custody of their sons, Sean Preston, 17 months, and Jayden James, 5 months.

"She has told Kevin more than once that she is sexually attracted to women and men equally," says the pal. "He wants to show that she's not such an angel after all."