We present the results of an investigation into the biographies, letters, and archives of approximately 50 well-known figures in Western intellectual and artistic history in the post-Enlightenment era. In this article, in the interest of space, we have limited our remarks to the biographies and partners of Virginia Woolf, Frida Kahlo, Max Weber, Edna St. Vincent Millay, William Moulton Marston, Erwin Schrodinger, and Victor Hugo. While some of these non-monogamous relationships are well known, some of the evidence of their existence has been ignored, misrecognized, or intentionally obscured. The results of this survey demonstrate that contemporary patterns of non-monogamies are deeply rooted in historical precedence. Our hope is that by outlining some of the themes in our historical findings we can help modern researchers better interpret their own quantitative and qualitative research. Additionally, we look particularly closely at relationships between metamours. A great deal of previous psychological and sexological research has focused on competitive behavior in sex and relationships, particularly competition between rivals. However, relatively little attention has been given to collaborative (or symbiotic) behavior. Our research has located a wealth of examples of metamours supporting one another in material, social, and psychological ways throughout their lives. Furthermore, we suggest that while our existing societal and social-scientific norms primarily focus on competitive sexual behaviors, much can be learnt from historically documented practices of consensual non-monogamy. These practices—however flawed—point to potentially emancipatory ways of living, loving and building relationships, families, and communities—as some contemporary research has demonstrated. Moreover, a future world might benefit from a turn to far more collaborative relationships—and such behavior is well within the realm of possibility.