To be clear, a wedding, pregnancy, successful career — all these imo are more likely to end with credits than a sexual event. Personally, one of my favorite game endings of all time:
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Whatever the ending turns out to be (and, to be clear: whatever side-relationships or issues are involved, I am assuming this game's primary storyline will always revolve around D + MC), ending on a pregnant "hm?" thought is OK with me ... but I would still desire significant revelations concerning those two before this game slides out the door in such a manner. That is, please give us some buildup - however subtle or even unwanted - and perhaps hit a double-edged crescendo to let out the biggest stresses at some point not long before the dusk of this game is reached. Things are feeling too ideal at the moment, as weird as that may sound for someone who would enjoy these characters finding general satisfaction in life. Life isn't so straightforward, though, and hitting a point where stresses (good and bad) have collected and self-imploded, with mixed fallout but still relief that it happened, can mean we've hit a point where everything is out in the open and ready to go somewhere beyond DMD.
At that point, you could end this game like
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and I would be happy because that would mean we have seen all that should be learned about these characters in the situations presented within DMD. If any future games have situations where some of them also become involved, then we could learn more about their paths in new contexts ... but for DMD it can end with all we really needed to know about them and not much more. No egregious fat tossed in for eye candy filler, no final fairytale ending (if anything, D's path should lead to a non-fairytale finale because her growth came from being the sleeping beauty type who needed saving and then became her own person). Maybe let it end with just the characterizations being clear, however questioning we might still be of their hinted futures.
Don't make this entirely easy, keep us dreaming! That could bode well for future games to anticipate from this team. But, given the player audience, I realize there may be the temptation to offer some subplot resolutions on a silver platter.