We still use the word cuckold today, but it's less a source of mockery. It's most often used to refer to a beloved sexual fetish. "Cuckolding" or "cucking" is when a man and his partner derive sexual pleasure from the woman having sex with men who are not her partner. Very often, her partner is "forced" to watch his wife or partner being unfaithful. It's a fetish that, like many others, is formed in a masochistic love being humiliated. In that way, cuckolding is a subset of the BDSM kink world. Like with many other kinks, what's appealing to men who are self-proclaimed cucks is the element of escapism, taking a break from the restrictions of their daily lives.