Metal Dragon by Lauren Esker

Stranded with an alien dragon!
Meri is a widow, consumed by grief for the husband she lost ten years ago. She never expected to be stranded on an alien planet full of vicious dinosaur-like wildlife … let alone with a tormented, silver-eyed dragon prince. He says he’s rescuing her. He’s definitely the only person who can protect her from this world’s monsters. But there’s no one to save her from her own treacherous heart, after she believed she would never love again …

As a slave to the Galatean Empire, dragon shifter Lyr lost everyone he ever loved, and walled up his heart in self-defense. Protecting Meri doesn’t have to mean falling in love with her. Even if she’s brave and beautiful, and everything that Lyr and his dragon could have wanted in a mate. But it’s just the two of them. No one is going to know …