Responses
I think at the beginning of the story they say that he hasn't had sex with any of the concubines. That for some odd reason he just keeps them to be nice or something. But I could be confused with another manga xD
beta
The story is still ok if you don't think too deeply, like how the main male mc slept with so many women lol. (It wouldn't make sense if he didn't had sex with them _(.-. )__/) But it's shoujo afterall, shoujo doesn't need any logic I guess.