"State-recognised marriage means treating married couples differently from unmarried couples in stable, permanent, monogamous sexual relationships. It means treating people in sexual relationships differently from those in non-sexual or caring relationships. It means treating those in couples differently from those who are single or polyamorous. It expresses the official view that sexual partnership is both the ultimate goal and the assumed norm. It expresses the assumption that central relationship practices – parenting, cohabitation, financial dependence, migration, care, next-of-kinship, inheritance, sex – are bundled together into one dominant relationship. And so it denies people rights that they need in relation to one practice unless they also engage in all the others and sanctify that arrangement via the state.
State recognition of marriage is thus discriminatory against the unmarried. It is also anachronistic. While some people do bundle together their relationship practices into one marital relationship, most people (including married people) live more diversified lives. We typically juggle blended families, care for elderly relatives, face family separation by migration, and manage multiple financial dependencies. It is no longer apt to regulate relationships on the assumption of marriage."
Clare Chambers, Against Marriage