The Lani People by Jesse F. Bone

Mixed emotion! Ha! The author of that cliche didn't even know its meaning! Kennon strode furiously down the dusty road toward Station One trying to sublimate his inner conflict into action. It was useless, of course, for once he stopped moving the grim tug-of-war between training and desire would begin again, and no matter how it ended the result would be unsatisfactory. As long as he had been able to delude himself that he was fond of Copper the way a man is fond of some lesser species, it had been all right. But he knew now that he was fond of her as a man is of a woman -- and it was hell! For no rationalization in the universe would allow him to define her as human. Copper was humanoid -- something like human. And to live with her and love her would not be miscegenation, which was bad enough, but bestiality which was a thousand times worse.

Although throughout most of the Brotherhood miscegenation was an unknown word, and even bestiality had become a loose definition on many worlds with humanoid populations, the words had definite meaning and moral force to a Betan. And -- God help him -- he was a Betan. A lifetime of training in a moral code that frowned upon mixed marriages and shrank appalled from even the thought of mixing species was nothing to bring face to face with the fact that he loved Copper.