Guarding Shadows by Aly Stiles

An emotional rockstar and military romance that can be read as a standalone.
Her demon stalks her.
His demons haunt the shadows of his head.
Internet star turned rocker Quinn Wylder never asked to be famous. So when she starts receiving disturbing messages while on tour with her new band, her reluctant dream quickly becomes a nightmare.
Army veteran Tanner Clarke never asked to be medically retired. But when an injury and PTSD diagnosis force him out of service, he’s left lost and alone in a civilian world that doesn’t seem to have a place for him.

It was the perfect solution: the compassionate angel who needs security hiring the haunted warrior trained to protect. But the biggest battle they face may be one they never saw coming—guarding a body is nothing compared to protecting a heart.