Two to Tango by Nicola Cameron

Rory MacLellan, AKA the Highlander, is the most successful interstellar art thief in the Known Worlds. Unfortunately for him, he also has a conscience. So when he runs into a suicidal museum worker during his latest job, he has no choice but to stun the man and rescue him from certain death.

Dr. Dmitri Grigoryev was an up-and-coming exoarchaeologist until a disastrous dig left his career in tatters. Hungry, broke, and desperate, the last thing he expected was a dashing thief to come along and ruin his suicide by saving his life.

With interstellar police on their tail, Rory and Dmitri reluctantly join forces for a major heist. But will their simmering attraction get in the way, or pull them even closer?