STANDISH – A 29-year-old Standish man was shot to death after confronting his former girlfriend and another man at a house, police said. Christopher Denis, who is from the Steep Falls area of Standish, was shot at about 11 p.m. Monday by Matthew Perry, 23, inside Perry’s home on Route 114, said Stephen McCausland, spokesman for the state Department of Public Safety. McCausland said Denis went to Perry’s home after finding out that his former girlfriend, Susan McNerney, 36, of Limington, was there, along with her teenage son. Denis and McNerney had broken up in the past couple of weeks, McCausland said, but he didn’t know the nature of the relationship.