Away from You by Jess Mastorakos

Lance Corporal Matthew Mills returned home from his first deployment with more than just a bullet wound. While he knew that injury would heal, he feared the invisible ones never would. He couldn’t trust his own mind anymore and the only way to keep Olivia safe was to push her away … maybe for good.
Olivia wanted nothing more than to stand by her husband while he battled PTSD. If he needed time and space, that’s what she’d give him. But how long was too long? Just when she was about to lose hope, fate and a few meddling friends stepped in.
A week in the woods at Big Bear Lake promises relaxation, fun with friends, and adventure. Without the pressures of the outside world, Olivia hopes she can convince him that their love is worth fighting for. And as much as it scares him, Matt can’t help but want to let her.