Destination Alien Treasure by Dee J. Holmes

Archeologist Temperance Vale is hot on the trail of alien artifacts. She’s ready to make the find of a lifetime in an ancient temple—until she discovers her dig site is overrun by evil body snatchers and she escapes into the arms of a muscled alien warrior.
Irax of the Apex’ir is the only one of his brothers who can enjoy no-strings attachments. Not that he’s interested. He came to earth to do one thing: kill his enemy, the infectious Fever. Then he saves Temperance. Brilliant and fiery, she’s like nothing he’s seen in a thousand galaxies—and she might be the distraction that gets him killed.
On the run in the long-buried ancient temple and tangled in growing desire, they struggle to reach the heart of the temple before their enemies. That site holds the key to the Fever’s power. And if Temperance and Irax fail to stop them, the Fever will burn across the galaxy.