It does. People who do that are exceptionally vile. The question at hand, though, was not the vileness of the killer but the amount of killing various categories of killers do. From conception to birth, "mommy" is a greater threat to a child's life than "mommy's boyfriend" is to a child from birth to big enough for effective self defense. Even so, the original point that genetically unrelated boyfriends (and girlfriends) are a serious threat to children, especially in some socioeconomic groups, is valid