Arten by Ella Blake

These aliens take “first contact” to a whole new level.
After teaming up to free a fellow Baylan and his human mate from a secret alien testing facility, Arten Dal-Allean has been keeping research scientist, Chloe Riker, safely in hiding. Now, the powerful people running the facility want her dead and the details of a human-Baylan peace agreement make taking her aboard his ship a big risk in the fragile negotiations. When she’s abducted from under his nose, Arten has to decide how far he will go for a woman who can never be his. Chloe may awaken all his protective and passionate instincts, but no soul marks appear on his chest to indicate she is his biological mate. Arten has always played by the rules—he made most of them—but how many will he break to make her his?
Chloe Riker fell for Arten long before they met. Their secret correspondences, and work to free Baylan test subjects, broke down all her walls. She’d hop on his alien base ship and into his bed forever, but her touch doesn’t seem to trigger the soul mark that would signal their true mating, and only humans who are true mates of an alien can reside on a base ship. As Chloe’s past catches up to her and powerful forces bent on revenge close in, Chloe has to use her wits to save herself and convince her alien lover to break a few rules.