I discuss a certain kind of emotionally charged negative reaction to defences of non-monogamous love, which I call collective-identity reactions. Expanding on work by Audrey Yap and Jonathan Ichikawa, who consider defensive reactions grounded in individual identity, I argue that collective-identity reactions are characteristically associated with claims about who we are, and motivated by a sense that the relevant we is in some way under threat. Looking into which we might be threatened by defences of non-monogamy, and why, reveals that this apparently personal subject matter is in fact entangled with global political issues like capitalism and American cultural imperialism. I conclude with some thoughts about ameliorative strategies for situations structurally similar to this one.