Cheating yeah I was talking Maxine first and foremost, the other is in a way more a business deal that involves sex.
Then would you call being a porn actress or cam girl also prostitution as such normally? Fair enough if do, the line is blurred enough, but some will vehemently deny that. Remember she does not know she is dealing with a demon with other goals instead of working on a series of movies for a pervert audience with a regular main male opposite.
The harem, well technically it will be I guess. Somehow worshippers though might be better based on how MC develops in future and how much he will keep caring. That is one way he seems to differ from most or all others of his kind after all, but will it stay that way as he grows.