How do you even willingly achieve being cuckolded? You can't communicate it, otherwise you're just an open couple or something.
So, do you like pick partners with terrible track records on fidelity and hope they keep going? But to satisfy that fantasy, you have to know, so you're forced to be a creep and track or follow your maybe cheating half.
Or you've got to find an actual sadist or psychopath that'll openly cuck you and rub it in your face just to see you suffer. But if you show them you actually like it, they might stop just to piss you off or turn violent.
Sounds like a lot of unnecessary and unhealthy steps for a fetish...