A novel mode of gel toughening displaying crack bifurcation is highlighted in phase-separated hydrogels. By exploring original covalent network topologies, phase-separated gels under isochoric conditions demonstrate advanced thermoresponsive mechanical properties: excellent fatigue resistance, self-healing, and remarkable fracture energies. Beyond the phase-transition temperature, the fracture proceeds by a systematic crack-bifurcation process, unreported so far in gels.