Loathing a Landon by Ruth Cardello

Cooper Landon knows what it’s like to be left behind, lied to, and betrayed. At sixteen, angry and broke, he tried to rob a small-town hardware store. Instead of money, what he got was a good beating and a second chance. Pete Glenford took him in, taught him he wasn’t worthless, welcomed him into his family, and gave him a purpose.
A decade later, Cooper lives in a small town, works in a hardware store, and uses what little money he has to locate and help runaways. He can’t change who he was before, but he’d feel good about his new life if it wasn’t for one minor issue—Pete’s daughter. She never wanted him in her home, never trusted him with her parents, and doesn’t believe any of his lies.

He definitely shouldn’t have slept with her.