Zayn by A.R. Ford

Gracie Thomson is wrongly convicted of a crime on earth. She finds herself exiled on Lonus N88. All she wants to do is find a way to survive. At least, that is her plan until she meets the enigmatic warlord ruler of Lonus N88—an alien who awakens her heart.
Warlord Zayn Bolden must produce an heir to ensure his uncontested reign of Lonus N88. Things are complicated. He is nearly assassinated and jilted on the same day. His trust in females is nearly destroyed. Zayn finds Gracie, a human female who crash-landed on his planet. She gives him hope, love, and her undying devotion. Until his past comes roaring back with brutal force to rip them apart.
Will Zayn overcome the demons of his past in time to save Gracie and Lonus N88? Or will she disappear from his life forever?