Forever Lasting by Kathleen Brooks

Cassidy Davies is used to being seen as the youngest in the huge Davies family. She’d grown up with too many overprotective brothers and cousins to count. So, she learned how to be invisible. That is, after she learned from her family how to be a spy, how to be an elite soldier, and how to bat her eyes and smile while taking a person down.
Now a government asset, Cassidy gathers information for the government or is a lone assassin. Whatever the government needs, she delivers. But this case is personal. She’s been called to help an old friend stave off a coup. Only this time, she may need some help. She just doesn’t know who it is that keeps showing up exactly when she needs it or how to find him when things go sideways. He’s always just a shadow in the night, but she’s beginning to feel as if he might be more than that.
He’s always in the shadows. No one can know his involvement with government missions or the fact that he has one weakness: Cassidy Davies. He first saw her when they both went to rescue the same person, yet she doesn’t even know he’s always got her back or that he even exists since she’s never seen him. She has no idea he’s the one who clears the way for her escapes, when she needs it. But when Cassidy’s life is in danger, it’s time for him to step from the shadows to save the woman he loves.