Lantana (2001)

Sometimes love isn't enough.

Plagued with grief over the murder of her daughter, Valerie Somers suspects that her husband John is cheating on her. When Valerie disappears, Detective Leon Zat attempts to solve the mystery of her absence. A complex web of love, sex and deceit emerges -- drawing in four related couples whose various partners are distrustful and suspicious about each other's involvement.