If you’re my age, in a heterosexual marriage in a North Yorkshire suburb rather than a Portland, Oregon polycule, there’s a spectrum of options for how you may view these unions, ranging from “harrumphing great-uncle” to enthusiastically onboard, with a real danger of sounding like a groovy vicar, effortfully down with the kids, when discussing it. I’ll run that risk: groovy vicar here, reporting for duty, to address a few harrumphing points. The HGU (and I assume he’s not a homophobe, just a bit baffled) might say something like, “Aren’t these just friendships? Why treat them as something different? Why get married?”