That's exactly what has been promised in earlier dev blogs if you go back far enough, although the ETA on it is still unknown at this point since it was cut from the initial release.
I browsed ci-en and found this article referencing sex scenes
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The relevant portion:
About sexual function
For those of you who have recently discovered me, you may not know this yet, but I will be making a sex scene in this game as a bonus feature. Since it is a bonus, it has no connection to the main game and will not appear in the game unless you enable it in the options.
The sex feature will be the last to be made. The other parts will be completed first, and the sex feature will be made after the game is complete. Due to various circumstances, the release date needs to be fixed to a certain extent in advance. Therefore, it is possible that the release date will come without the sex feature being added in time. In that case, we will update it at a later date.
Then this part from the release date announcement (
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):
Also, please note that the sex function is not included in the initial version. It has not been made yet.