How common is polyamory? First new national survey on this: 3% of adults report currently being in a CNM relationship 12% report having ever been in a CNM relationship. CNM = Consensual Non-Monogamy
Ideas have consequences: "National Survey Reveals Generational Differences in Consensual Non-monogamy": 
Still, younger adults are markedly less supportive of monogamy and more open to consensual non-monogamy (CNM) 👇🏽