Why are men never seen in the play The House of Bernarda Alba?
Lorca is more focused on depicting the restrictive and oppressive lives of Spanish women than their actual interactions with men. The men merely evoke the women's emotions, actions, and reactions; and so from a technical viewpoint, just their mere mention can serve the function of creating the necessary conflict/tension needed to serve the play. From a literary standpoint, men become virtually symbolic as opposed to realistic characters. Lorca often points out the evident hypocrisy in Spanish culture (and, indeed, in most cultures) where men are allowed free sexual expression and women are punished and even condemned for it. By not introducing the male characters into the scene, the audience is allowed to experience the full range of what sexual repression can effect in women--in this case--a family of women. Pepe el Romano becomes symbolic of freedom from the restrictive environment the matriarch, Bernarda, has created within her own home as well as the sexual repression within the culture itself. Is it no wonder the sisters are willing to betray one another for this promise of freedom?
As a dramatic device, not including Pepe el Romano as an actor on stage adds to the allure all the women feel for him. The audience can create any visual image they have of this paragon of masculinity who has caused so much angst among the sisters--so much so that tragedy becomes inevitable.