It comes into play with humans because rather than wanting the females’ attention to breed, they simply want the females’ attention - and the previous males’ children are just a distraction.
It comes into play with sub-humans perhaps. Real men are not intimidated by children sired by another man before the woman became their love interest. He takes them in as his own to nurture. But I understand what you are saying, this man is an animal, and with that assessment I agree.