Little Black Book (2004)

Stacy, a talk show producer, becomes increasingly obsessed with uncovering her boyfriend Derek's romantic history. Partnering with her colleague Barb, she tracks down Derek's former flames under the pretense of conducting interviews for a segment. However, the revelations she uncovers only deepen her uncertainty about their relationship. As she forms a bond with one of Derek's exes, her initial intentions spiral out of control, forcing her to confront the complexities of love and trust.