K.L. Noone 
In Lines of Light [EPUB ebook] 

Federated Planets ambassador Tamlin Rye is headed home, having just finished a successful negotiation. Tam’s looking forward to some rest … but the beautiful mysterious captain of his courier ship is more tempting than restful.Captain Valentine Perrin doesn’t sleep well. He might be young, but he’s seen his share of difficult missions. His starship’s observation deck offers solitude on those nights … until his new passenger interrupts.And, on this starlit night, Tam and Val will both find exactly what they need.