That is a simple fact of life. If they should impregnate a female this afternoon, they can do the same to another female this evening. I speak not here of morality but of physical law.
Males can spread their genes far and wide.
They have no real limitations and therefore they are not the important ones in the area of perpetuating the species. To the females have been given that sacred task. If females do not have children of the same species as themselves, their species dies exactly that much. Females are the limiting factor in perpetuation of the species. Females can only have a limited number of children in their lifetimes.