Skinwalker by Cyndi Friberg

Jaron travels to another dimension to rescue Velmar, a good friend and fellow rebel. While sneaking through the Cretzian fortress Jaron encounters another captive, a feisty human female. Nikki offers to help Jaron rescue Velmar but only if they agree to return her to Earth.
Jaron accepts Nikki’s condition, but isn’t sure he’ll be able to let her go. She intrigues and arouses him in a way he has never experienced before. Though he senses deception in Nikki, he is also convinced that she’s his soulmate. Is she an innocent victim of their mutual enemy or a cleverly planted spy? Jaron must determine if the female he is falling in love with is friend or foe and convince her to accept his claim all while fighting a contentious civil war.