Little Black Book(2004)

Overview:

Determined to learn about her boyfriend's past relationships, Stacy -- who works for a talk show -- becomes a bona fide snoop. With her colleague, Barb, Stacy gets the names of Derek's ex-lovers and interviews them, supposedly for an upcoming show. But what she learns only adds to her confusion, and her plans begin to unravel when she befriends one of the women.