It is seen as a negative thing because his woman, girlfriend or whatever, is involved with other men. Even though it's streaming and not a direct, physical, relationship, it is still a woman sexually enticing other men. He is a cuckold because she is "seeing" other men in a way. It doesn't matter if he fucks her because a million guys jerk it to her giving JOI on Twitch, or whatever slutty shit she does.
E: oh, it's onlyfans? That's a million times worse. Asmon is as much of a cuck as Ian.