As one reviewer put it, the PTSD was handled reasonably well. There for a while, various romantic suspense authors gave me the feeling it was the trope du jour and they researched just enough to be dangerous. Worse, they gave their heroines magic hoo-hahs which cured whatever ailed the heroes.
Not this time. In fact, the longer and more involved the H was with the h, the worse it became. It stemmed from his inability to protect some people when a space station was destroyed, and his subconsciousness was fretting about his being able to protect the heroine. Eventually, she'd had enough - he wouldn't seek help, and he wouldn't talk about it - so went on a mission that took her away for a couple of months. Ironically, she sent him a message telling him he either got help or she was gone at about the same time he sent her one telling her he couldn't live without her and was going to seek help. The best part? Disaster struck, forcing her and the others (that didn't get eaten) to run for their lives after sending up a distress signal. He went out to rescue her, and neither read those two messages.
As an aside, the dude on the cover has goose bumps. hehe.