Cukold means that you basically have another man take your wife- and because you are the weaker of the two men, you are unable to prevent it or protect her virtue from the intruder. I'm not sure if being a cukold man means that you take pleasure from being cukold- or the word just refers to the act itself. Time for a wiki search :)
Lots of guys kinda get off on it, as demonstrated from this thread, I guess. The term has been around in literature for a LONG time- Shakespeare was a fan.