Everything you need to understand or teach The Expats by Chris Pavone.
When Kate gives up her secret career with the CIA to follow her husband's job to Luxembourg, she believes she is doomed to a life of laundry and play dates for their sons. Instead, she finds herself investigating two suspicious new friends (Julie and Bill) and her husband (Dexter). The new friends are actually FBI agents. Dexter is under investigation for international cyber theft.
Kate feels guilty for investigating her husband, for not telling him about her secret career, and for her role in the unsanctioned murder of a Mexican political figure. She works through this guilt and finds the thrill she needs to keep her life interesting in Luxembourg. Kate's investigation garners her the confession she needs in order to keep her family in tact and gain a new job with the CIA.