Do not trust this too much since I haven't read the novel, but in some forum it says that as we already know, for some reason our MC's soul reaches the world/domain/dimension of Asura, Eris and the other two goddesses: Jamir and Spica. At first not even Asura knows why or how Kousuke arrived and then she asks Eris to bring him to the Ever Spring Garden.
While Kousuke is in the Garden, Asura discovers that he has the potential to become a god... and this is what seems to made sense of that our MC has divine powers and incredible luck with women: and is that in this world/domain/dimension there are no "male gods". That's one of the main reasons why she tells Jamir and Spica not to contact him yet. In the manga it's not stated yet, but apparently there are even more goddesses and Asura fears that chaos would start if the other goddesses discover Kousuke and that would definitely affect the world of Aesgard.
So yeah, your theory might be true. And that Asura and the other goddesses only send him women, and even encourage him to have multiple partners, maybe it's for him to learn to handle "multiple wives".