I will present a new variant of Benders method combined with a domain decomposition heuristic to solve discretely-constrained mathematical programs with equilibrium constraints (DC-MPECs). These bi-level, integer-constrained problems are important for a variety of areas involving infrastructure planning (e.g., energy) although they are computationally challenging. The numerical difficulties arise in that one must treat a lower-level optimization or complimentarily problem as well as the discrete nature of the upper-level planning variables. Thus, we combine both integer programming and equilibrium modeling. Lastly, we provide numerical evidence that the proposed new method works; the domain decomposition heuristic has been implemented with MATLAB-TOMLAB interfacing for small-size problems and MATLAB-GAMS interfacing for large-size problems.