Mission: Guardian Angel by Laurann Dohner

Ever since her friend Vivian mated a Veslor, Abby Thomas has been curious about the mysterious aliens. She also has a vested interest in making sure their newfound relationship with United Earth is a success, prompting her to take a job on a military vessel to ensure the Veslor grouping stationed there are treated fairly. It doesn’t hurt that they’re easy to look at. When one Veslor in particular catches her attention, she hopes he’s nothing like the humans she’s dated, who were only interested in her bank balance and connections.
Drak and his Veslor grouping quietly endured unfair treatment aboard Defcon Red…until a beautiful spitfire spoke up on their behalf, earning herself nemeses among the ship’s fleet. When those foes try to silence Abby, Drak makes it his mission to protect her. The harrowing experience quickly bringing them so close, Drak is determined to make Abby his mate…if her enemies don’t ruin his chance, permanently.