Strength of light-matter interactions and radiative dynamics of emitters could be controlled with structuring of electromagnetic environment. While local and cross density of electromagnetic states are routinely used for predicting total and radiative decay rates in the weak coupling regime, resonant nanostructures offer going beyond this description, giving rise to new phenomena. Correlated time-evolution of a strongly coupled emitter-nanoresonator system and nonradiative channels are shown here to predefine the radiative decay dynamics and lead to substantial shortening in characteristic emission times. Quantum formalism, based on stochastic Hamiltonian treatment of radiative and nonradiative processes, was generalized for describing light-matter interactions in vicinity of open nano-resonators. The developed theory was subsequently applied to spontaneous emission dynamics of emitters, situated next to metal surfaces, supporting stopped light resonant conditions. Over four orders of magnitude lifetime shortening was predicted to be detectable in the far-field. The interplay between strong and weak coupling regimes, enabled by resonant nanostructures, could serve as a platform for ultrafast opto-electronic components, fluorescent labels and others.