An off-duty NYPD cop shot her ex-girlfriend and killed the woman’s new lover after catching the duo together at a Brooklyn home on Wednesday night, police and sources said. Yvonne Wu, 31 years old and a five-year veteran of the force, opened fire on the pair at the ex-girlfriend’s house on 19th Avenue near 79th Street in Bensonhurst at about 5 p.m., according to police and law enforcement sources. The jilted lover was waiting outside of the home when cops arrived and admitted in a very “calm and collected” manner that she shot “someone” inside the house, NYPD Assistant Chief...