The Soldier and the Cowboy by Vanessa Gray Bartal

Bailey Dunbar has been dispatched to South Texas. Her father found her a pity job to get her out of his hair, and who could blame him? She was driving him crazy. She was driving everyone crazy, herself included. Being a marine was all she’d ever known, all she’d ever loved. Who was she if she wasn’t one anymore?
Calhoun Ridge was once a golden boy, a man of promise. Now he was a broken down old cowboy, all because of a mistake he made ten years ago, a mistake that set the trajectory of his life, threatening to ruin everything, including the cattle ranch that had been in his family for four generations.
They were two broken people–broken dreams and broken lives, both strong and resilient in the face of too much pain. They shouldn’t have worked, shouldn’t have wanted or needed each other. But they did, becoming fast friends at a time when friendship was dangerous for both of them. As Bailey begins to help Cal untangle the danger that surrounds him, they’ll have to tread carefully because the only thing scarier than losing their lives is losing their hearts.