Anyone made your partner a textbook CUCKOLD

In modern sexual contexts, cuckolding describes a consensual dynamic where husband derives pleasure from wife having sex with someone else. As per textbook definition, A cuckold is traditionally a man whose wife or female partner is sexually unfaithful, often used disapprovingly or humorously, though it can also refer to a man unknowingly raising another's baby.

A women is only knows who is the actual fathar of her child. Is any  woman here who knows the child whom her husband think as his own, is biologically from any other man?