The incident happened around midnight Monday on the 200 block of Edgewood Street.
According to police, the old boyfriend who they say was armed, broke into the house to confront the new boyfriend.
There was a confrontation in the kitchen, and the new partner shot and killed the ex, police say.
The new boyfriend fled the scene, but police apprehended him, a short distance from the house.
Police say the women's two children were asleep in the house, but were not hurt.