Sleeping Dogs Lie (2006)

An impulsive sexual encounter from her past haunts Amy, an otherwise seemingly normal young woman with a bright future and nice-guy fiancé. But her fiancé has suggested that the couple be completely honest and tell each other everything! When Amy finally relents, encouraged to tell the truth by her coworker and mother (neither of whom really knows what she has to disclose), and reveals her secret, all hell breaks loose.