The Birthday Card Boyfriend by Krista Sandor

Isabelle’s not in the market for a relationship—not even close. But she can’t stop thinking about her one-night stand with a stranger on his birthday.
The rules were simple: one night of passion, no names, and all the cake.
Kieran wasn’t looking for anything more than a fling.
And then he saw Isabelle and found his birthday wish.
What he didn’t expect was for his mystery woman to stroll into his hometown of Starrycard Creek, Colorado, as . . .
His rival.
Now, he’s stuck with her night and day.
As they battle over the future of the town, the stakes become higher when a ruthless developer eyes the quaint mountain abode and jeopardizes everything Kieran and Isabelle hold dear.