VTubers are the evolution of the waifu where you can now be cucked by your waifu (or oshi who cares). Before, there was only fanart of your waifu in which you could self insert as the dude fucking them or imagine its someone else, but there was never anything real to back up that fantasy.
Now when a vtuber goes and fucks someone, they can simultaneously cuck millions of people at once. It's not the same as the voice actress of a waifu fucking someone, because they were never the character they portray in the same way a vtuber is. So much of what you fall in love with in a vtuber is their actual real life personality. Even considering that the extent to which they play a character varies between vtubers, it's virtually impossible to be 100 percent fake and have nothing of your actual personality slip out when you're streaming for hours at a time, meaning most give up and just stream as themselves even if they were playing a character at first.
Do you truly believe any of these women, who as most of us know through doxxing are at least attractive enough that they'd never have to worry about being able to get laid if they want, will stay abstinent just for the sake of people they don't know? Even if you have no hard evidence leading to believe they are getting pounded by bbc on the reg, it's only a matter of time. Watching, waiting for that one fatal slipup where a male voice comes on stream or they accidentally fail to refer to their boyfriend as "brother" or "dad" and the facade all comes crashing down. At that moment you will know a form of cuckoldry that before was not even possible, and it will be a shared sense of dread with upwards of millions of men all at once.