Entwined with the Dryad. The Woodland Beasts Romance Trilogy, #3

If they fail, they'll lose not only the world they've left behind, but each other forever. Lorraine would sacrifice anything to save Ash-even the enchanted bond that kept them alive in his realm. Now, back in the mortal world with Ash but without his powers, she faces a harsher reality than she ever imagined. Ash, no longer an immortal Drus warrior, is haunted by the loss of his magic, his home, and the life he once knew.
Yet, an ancient story hints at a way to restore everything he's lost. To reclaim his powers and return to the mystical Vale, Lorraine and Ash must confront deadly new foes, fierce betrayals, and their own fears of what lies ahead. But this time, magic may not be enough to save them. If they fail, they'll lose not only the world they've left behind, but each other forever.