This book is on pre-order until book delivery arrives. 
 
Powerless to Resist (Hestaesia #5) by KL Thorne:
 
Since betraying his king and leaving Awrelwood, things have been less than ideal for the faerie captain, Quinn Morgwell. He has turned his back on all he knew, and though he has sworn his allegiance to the demon king, no one is in a rush to trust him.

But Morgwell has a trick up his sleeve - a mysterious, ancient power that renders him invulnerable to majick.

Coven harbinger and fearless witch Tabitha arrives in Rosenhall Castle alongside the demon king and his cohorts, ready for war. With her powerful coven sisters at her side, the witch is confident in their success and doubts nothing… Until she meets Captain Morgwell.

From their first meeting, Tabitha has her heart (and nethers) set on the handsome faerie, but to her surprise Morgwell is in no hurry to return her affections. The telepathy she has grown so reliant upon ceases to function, leaving the proud witch with no choice but to woo the captain the old-fashioned way.

In no time, Tabitha realises she has bitten off more than she can chew with the handsome faerie captain. When her majickal protection fails, the witch finds herself having to make an impossible choice between betraying a powerful ally, or sacrificing everything that she holds dear.

Has the powerful witch finally met her match, or will she triumph in both love and war?