Girl Power
Rich is known as a major feminist poet. Her career and work were devoted to championing women's causes and reflecting the too-often-ignored experiences of women in the language of poetry. That's precisely what's going on in this poem, although it's interesting to note that "Living in Sin" comes at a transition point, one when Rich was writing about issues that mattered to women, but still found herself unable to write in the voice of a woman. This all changed as she fully developed her feminist voice, but this poem comes from this period where the poet's attention was developed, but her methods of presenting her concerns were developing.