His Duty to Serve by Shanae Johnson

A former Special Forces operative is on a mission to clean up his bad boy image, but falling for his exes’ baby sister certainly won’t win him any medals.

Dorie Reyes has always lived in her perfect big sister’s shadow, watching as she effortlessly stole the heart of the boy Dorie had always crushed on. Only to not stand by him when he needed her and leave him broken-hearted. Now, to save their business, the Reyes sisters need access to their inheritance. But a stipulation that they must be married first puts a wrench in their plans. When Dorie’s big sister pops the question to her convenient ex-boyfriend, Dorie believes her unrequited love story is over before it ever begins.
Aaron comes back from war hoping to gain acceptance from the town that turned their back on him. He’s no longer the bad boy he used to be. He’s a hero now, scarred by battle but driven by a deep desire to make a life with the woman who broke his heart years ago. When she proposes a marriage of convenience, he thinks this is his chance. But as he spends more time with his future sister-in-law, it becomes clear that they have more in common with each other and share a deep connection that cannot be ignored.

Now Aaron’s faced with the fact he’s falling for the wrong sister, and Dorie’s faced with the guilt of stealing her sister’s fiancé. They’ll have a heartbreaking decision to make—give up on their love or risk everything to be together.