Strangers — Gardner Dozois

Living in a decadent Earth colony among the alien Cian on the planet Weinunnach, human artist Joseph Farber falls in love with Liraun, a humanoid Cian, despite the fact that love between races is forbidden, and allows himself to be genetically altered so that he and Liraun can be together, but the fundamental differences between their races could lead to tragedy. Reprint.