The pilot reported that he was seated in the right seat and the pilot-rated passenger of a twin-engine airplane was in the left seat. During the approach for landing, the pilot had his hand on the throttles and was providing input on the flight controls. The pilot-rated passenger reported that she also was giving some input on the controls with the pilot coaching her. The pilot reported that before landing, he asked the passenger to assure that her feet were not on the pedals. The passenger reported that on touchdown, the airplane bounced, and she released her hands from the controls so that she would not interfere with the pilot’s actions. The pilot reported that after the airplane touched down the second time, the airplane veered to the left. He added full right rudder input then added full power to the left engine in an attempt to regain control. Braking action is not available from the right seat position. Despite his actions the airplane exited the left side of the runway and came to rest in a ditch. The aft empennage separated, and the wings were substantially damaged. The extent of damage was consistent with a hard landing. The brakes were not examined.