Once Upon A Bended Knee (Spy Springs #2)
Vanessa Gray Bartal

Lately it had been better, because Nathaniel was stationed in San Diego and often out of the country on secret assignments. But when he returned to their small Texas town to visit, that was when Katie's agony arrived, too. Now it had become too much to bear. As much as she loved him, she had decided to avoid him by any means necessary, even if it meant occasionally plunging out of sight, no easy task in such a small town.
But as determined as Katie was to hide from him, Nathaniel was as determined to find her. And whatever Nathaniel Ridge set his mind on, Nathaniel Ridge got, even if it meant tossing her over his shoulder and carrying her out of town. He needed to know why Katie kept disappearing, even if her answer changed their lives in irrevocable ways. Because Nathaniel had never had a friend like Katie. He couldn't lose her, even if it meant upending his entire life and telling Katie his deepest secret.
The second book in the sweet and wholesome Spy Springs series, a spinoff of the popular Spies Like Us series.