The Guardian's Honor – Marta Perry

Coast Guard officer Adam Bodine finally finds his long-vanished great-uncle. But the secretive elderly man has adopted some new kin…single mother Cathy Norwood and her disabled little boy. Adam is grateful when Cathy convinces his relative to reunite with the Bodines. Until he learns why she's so eager. Though his heartstrings are tugged by their plight, he knows he doesn't deserve them in his life–not with his past. Unless one big extended family can teach Lieutenant Bodine something about love and honor.