Director Amat Escalante uses a fantasy creature to explore the sometimes ambiguous relationship people have with sex in his film "La Region Salvaje" (The Untamed), which had its premiere at the Venice film festival on Monday. The drama tells the story of Alejandra, a young mother of two, played by Ruth Ramos, whose boorish husband Angel, portrayed by Jesus Meza, has an affair with her gay brother, Fabian. Their family triangle gets twisted furthe…