According to the flight instructor of the PA-44, while conducting a training flight with his student, he simulated a left engine failure and the student proceeded to enter the traffic pattern for runway 19. Upon touchdown, "the rear of the airplane and the right wing raised off the ground" and the flight instructor instructed his student to "Go-Around." The airplane began to track left and the flight instructor took the controls. He was unable to maintain directional control, and the airplane exited the runway collapsing the left main gear and substantially damaging the airplane. The student pilot reported that the flight instructor simulated the engine failure by "cutting off fuel to the left engine," and the flight instructor reported he must have "forgotten to turn the fuel back on" during the go-around. No mechanical deficiencies were reported with the airplane.