The Zephyr Prince (Three Brothers Fair #3)

Andy is the eldest son of the ruling kelpie family. His two brothers have found their lovers, in accordance with an often-misunderstood prophecy. Now it's Andy's turn -- however he must first make peace with the fact that his match is a gender-switching air being.

Nubes, both king and queen simultaneously, seeks Andy only as an answer to the prophecy. Slowly, however, as respect and lust grow, both Andy and Nubes find out that they can no longer survive without one another.