(Spoiler alert!) Is that scrawny boy actually a man? I love it when the black man lifts him from the ground fucking him and he moans like a high pitched girl!
In response to the original question, I don't even think that it is much of a secret. I know many cuckolds would vehemently deny it, but why go so far out of the way to invite another man into an otherwise monogamous relationship? If you want monogamy, you already have it and if you want another woman or swinging, convince your wife to go bi. But this particular fetish seems focused on men who want another cock; the excuse is saying that it is for their wife.