Xen by Elle Harper

Leader of her people. Their savior, who brought them back from the brink of destruction and helped them thrive. Honored above all others. Practically worshiped.
It’s lonely up on Aavi’s pedestal.
The leader of the Izothians has few friends, and even fewer lovers. But when one of those longtime friends, her science advisor, Xen, guesses what his Queen has been craving, he’s more than up to the task of providing her with every pleasure, and punishment, she could ever desire.
And when a new arrival on their planet captures the Queen’s interest, Xen makes sure she’s able to sate that craving, as well.
But Aavi knows that the life of a ruler is full of false friends and that true loyalty is hard to come by. It’s possible that opening her heart to anyone, even her dearest friend, will spell her demise.