What do you mean by "civilized jurisdictions"? I don't know any place that explicitly adjudicates the separation of unmarried couples as though it was legally equivalent to a formal divorce. You'll have to be more specific.
Unmarried couples may fall into one of two types: common-law marriages and meretricious relationships. In the US, the former is approved by a vanishingly small number of states. The latter has no legal rights to property division or palimony without an explicit cohabitation contract. Even then, many states don't recognize palimony at all.
Unmarried couples may fall into one of two types: common-law marriages and meretricious relationships. In the US, the former is approved by a vanishingly small number of states. The latter has no legal rights to property division or palimony without an explicit cohabitation contract. Even then, many states don't recognize palimony at all.