I like sharing my partners and myself, not merely as kink but as part of our polyamorous life. Cuckolding for me has an aspect of negativity, like degredation, that is absent from how we do it. When I see my partners having sex with others, Im just happy, even if I dont join in.
We are also not really into humiliation (bit of namecalling is fine), but the really "hard stuff" we leave for others to enjoy. I know that when I love a person, love sharing them so others can enjoy their compaby as well and maybe see why I hold this person dear so much.
Its also probably really hard to cuck someone who cheerleads you enthusiastically during the act, instead of having to "endure" the whole thing.