Tempt Me Twice by Pippa Brook

Can amnesia lead to a second chance at love?

Phoenix “Griff” Griffin is the chief of the Mercury Ridge’s Fire Department. Known for being a serious, no-nonsense fire chief, Griff never gets hot under the collar. Except when it comes to his ex-fiancée, Mercy Taub.
Ten years ago, Mercy broke off their engagement and left town—without warning or a reason. So, when she shows up at the fire department asking to see her fiancé, Griff’s anger boils to the surface. How dare she just waltz back into his life like nothing has changed? But to Mercy, nothing has changed. To her, no time has passed at all. Because she has amnesia.
As tempting as it is to fall right back into a committed relationship, is it a risk Griff can take? He still has no idea why she left ten years ago. And now, there’s a ten-year gap in her memory. She could be married with kids for all he knows. What happens when her memory comes back?

But his heart has always belonged to Mercy, and staying away from her is impossible.