Marriage, as a social institution, manifests differently across states, cultures, religions, and individual contexts. In some settings, it continues to draw heavily from traditional norms; in others, it has undergone notable transformations. Yet access to and engagement with these changes remain uneven, often constrained by a complex web of state and familial controls. Matrimonial equality, and the structures that inhibit or enable it, are best understood through five intersecting paradigms: (a) state law; (b) cultural practice; (c) religion; (d) secularism; and (e) the family. These domains shape not only how marriages begin but also how they are maintained and eventually ended—whether through divorce or death—with Sharīʿah (الشريعة; Shari’a) law maintaining significant influence across many Muslim-majority societies.