I Do, You Don’t by Audrey Halliwell

Lara’s life shatters when her fiancé, Gideon, leaves her at the altar humiliated, broken, and betrayed. The woman responsible? Delilah, his childhood best friend, who’s always been just a little too close for comfort.
As Delilah spins her lies, claiming that Lara was unfaithful with another man, Gideon believes her and walks away. What he doesn’t know is that the man Lara allegedly had an affair with is her and Delilah’s shared, secret half-brother, Calvin. He also doesn’t know that Delilah intentionally lied to him, keeping their family’s hidden truth from both of them.

When Gideon overhears Delilah admitting the truth—that Calvin is the shared sibling between her and Lara, and that Delilah deliberately deceived him—Gideon realizes he made the biggest mistake of his life.