If I Lie by Corrine Jackson

When Sophie Quinn's mother left her father for his brother, Edward, she was dubbed the town slut, not only for cheating, but for cheating on a marine. Now, as a senior in high school, Sophie is walking in her mother's footsteps, loathed by everyone in her little military hometown. Why? Sophie got caught kissing a boy, and it wasn't her boyfriend Carey...a U.S Marine. Sophie knows there are ways to get rid of her ugly reputation, but doing so would hurt Carey in the process. When Carey goes MIA, Sophie is forced to decide which is more important to her: her reputation, or her promise to Carey.