I'm going to explain the appeal of cuckoldry since /vt/ doesn't get it and doesn't appreciate the vtubers who create or benefit from this content.
The entire thing is about the feeling of getting hurt, in short it's the good old masochism (in this case emotionally). Getting hurt feels good, to enjoy it fully you turn that feeling into power, fuel for your own lust.
When a female vtuber interacts with another male that isn't you (her fan), you need to look past the bad feelings in your heart and focus on the lust. The same works for a male vtuber that interacts with female that isn't one of his fans.
If you guys learned to have more fun you would understand the appeal of this fetish (which is quite popular)