Who is Luka the Butcher, Amana from The Tiger's Wife: A Novel and what is their importance?

Luka the Butcher was an artist and apparently a homosexual in the days when being either, let alone both, was unheard of. As a result, he left Galina to pursue dreams of a freer, truer life in the big city of Sarobor. The anger and rage associated with the failure of his dreams, seems to have fueled his attacks on the woman he was tricked into marrying. The tiger's wife who, the narrative also suggests, killed him in revenge.