Seeking Looking for games with helped corruption

[Herbii]

This may be a bit too specific, but something I really like is when a female love interest in a game helps you corrupt/romance others. Some examples are Parental Love (the sister helping corrupt the family), Single Again (one of the step-daughters helping with the other step-daughters), Midlife Crisis, etc. Harem is probably a given in this context, and incest is nice but not required.

 

[Guntag]

In Wife Trainer, some of the women you seduce or train can become your assistant or help you train other women. This is not the main part of the game, but it is not negligible at all (maybe more of such content than in the games you mentioned). You should really try it, there is a lot of content and replayability. There is an incest tag, but it's an infinitely small part of the game. Even if there is not harem tag, you can have multiple women living with you at the same time (but not all of them).

 

[Pretentious Goblin]

Jikage Rising - already-corrupted girls sometimes help corrupt others.
Nano-Control - ditto, at least for the mom and sister.
iNSight of you - central to the story, your GF helps develop mind-control tech to subdue your horrible boss. Optional harem with GF and her friend, but the boss isn't really part of it.