Stress corrosion cracking (SCC) and fatigue are major threats to the durability and safety of metallic structures. Although each mechanism independently degrades the material, their coupling results in accelerated and highly complex damage. Cyclic loading in corrosive environments accelerates crack initiation and growth, alters failure modes, and often leads to premature failure. This is critical in high-safety, high-cost applications such as offshore wind turbines, nuclear reactor piping, prestressed bridges, and aerospace components. Predictive tools for the combined influence of SCC and fatigue remain limited. Conventional design and maintenance approaches often treat these mechanisms independently, resulting in overly conservative or unsafe performance estimates. We propose a dual-phase-field chemo-mechanical framework to model the coupled interaction between corrosion and fatigue. Two phase-fields are employed: one for corrosion front evolution, including pitting and SCC, and another for fatigue crack initiation and growth, including the pit-to-crack transition. Mechanical straining acts as an electrochemical driving force, accelerating corrosion under cyclic loading. The formulation is implemented using the finite element method with implicit time integration, with displacements, phase-fields, and ionic concentration as primary variables. Numerical studies illustrate the mutual feedback between corrosion and fatigue will be presented. Localized corrosion reduces fatigue lifetime and modifies stress distributions, accelerating crack growth, while fatigue cracks enhance exposure to corrosive species, accelerating corrosion and redirecting corrosion fronts. The framework captures this bidirectional coupling, providing a unified tool to investigate the spatial and temporal interplay between mechanical and chemical degradation. By resolving both pitting and SCC under cyclic loading, it enables realistic, physics-based predictions of structural lifetime, identifying regions prone to premature failure and informing maintenance and design strategies. This approach provides a pathway toward improved service-life assessment and the design of more durable metallic components exposed to coupled mechanical and corrosive damage.