Significance We demonstrate that low-molecular weight asymmetric diblock copolymer melts can form multiple metastable liquid states at a common temperature, dependent on the processing history. Formation of ordered self-assembled micelles at low temperatures shapes the number density of the mesoscopic particles, which is preserved upon heating above the order–disorder transition temperature. Cooling returns the liquid to the same crystalline state reflecting a memory—a type of hidden symmetry—imprinted in the fluid. These surprising results are explained based on the large energetic penalty associated with fusing or fragmenting micelles in the highly structured liquid state. This work reveals concepts related to spontaneous symmetry breaking in self-assembled soft materials including surfactant-based systems.