Molt Brother by Jacqueline Lichtenberg
Science fiction is at its best when acting as an allegory for life. It can also be at its worst. I remember this at its best, but I fear that if I were to reread it, the opposite might be true. The story of love across species and a human man being indoctrinated into an other culture, I mean even writing this makes me cringe a little.
Anyway, I hope this stands up to time a bit better than my recollections of it do, because it has a fabulous Star Wars-esque cover and I remember being quite clever and insightful.