Dark Desires at Dawn - Divine Desires, #1

The Barbarian and the Goddess.Tessa is the Etruscan Goddess of the Dawn, worshipped by an entire civilization. At least, she used to be. Now her powers are weakening, and she's been targeted by a malicious god who wants to consume her remaining magic. She needs a hero and fast.preferably one who's good in bed because sexual energy boosts her magic. She seeks out Caligo, a barbarian whose sexual prowess is legendary...
Caligo is a fabled Cimmerian warrior determined to stay out of the affairs of the deities. He thought he'd learned his lesson after his last affair with a goddess left him barely breathing. But there's something irresistible about Tessa, something that draws him in. Now they're on the run from the God of the Underworld, and Caligo is Tessa's only chance to escape the encroaching darkness...