This paper explores a trade-off between structural longevity and energetic response for wave energy converters in irregular waves. To this end, a physics-based simulation methodology is developed which integrates both the hydrodynamic efficiency calculation and fatigue damage assessment. This methodology is embedded into a parameterised computational model by coupling analytical models for the simulation of both the pressure field and the hydrodynamic efficiency for a particular incident sea state, and a numerical model for the structural analysis of the system. The methodology is general but for this paper it is specialised for an idealised power-optimal bottom-fixed oscillating water column device. As particular case studies, a sea-state adaptive power-optimal configuration and a fixed power-optimal configuration were investigated and compared. The results reveal that the sea-state adaptive configuration not only provides the optimal hydrodynamic efficiency, but also leads to less accumulated fatigue damage.