I'm totally on your side! But I understand why people are skeptical about sandbox in porn games.
Make a good "sandbox" game much more harder and resource consuming than a linear format game. Developers often overdo with grinding. Grinding is not always bad decision in game design sense, but it should be fun, and even a fun grinding may get player tired, so then should be possible to shorten it or skip it completely.
Good sandbox porn games are rare! My favorites are text-based, and they have almost no to little cuckold(-quean)/sharing content in them
Yeah that's why Mijishi games are great.
Like having a netorase game with a non-linear approach, where you the player not necesarily decide directly but can influence. And this influence translates into different outcomes.
Like give your wife a bottle of wine.
Nothing happens.
Give your wife a bottle of wine, with the side quest "helping sailors relief themselves" completed, at least 200 reputation with the sailor faction, and wife "slutty" or "netorase" score of 80 out of 200.
Now when you return home in the night from your quest, wife is not there, MC decides to make a brief comment but nothing else.
You can choose between stay at home or decide and investigate. If you stay at home for the night wife wakes up next to MC in the morning, but extrangely enough she didn't change clothes and she looks all disheveled, slightly exposing her cleavage. And MC comments that her breath smells like cheap rum, like the one you remember they sell at the inn close to the harbor.
Now you may decide to investigate instead, because you remember that comment the Chief Sailor made to you "thanks for helping us all, next time you two can come and drink all night after our next travel! ". You decide to leave the house, directly to the harbor district, where the INN is located. Everything seems in silence, until you approach the tents where sailors usually sleep between travels. You hear a slurping sound in one of the tents, it gets more intense the more you approach, and once you are around 6 metters close you can finally see a text of dialog:
> Sailor: "Hehe, that's a good blowjob missy, not even the whores they send to our ship give head like you"
> Wife: "(slurp, slurp) Ahhahh Thank you, i've had a lot of practice after all (drunk sound)"
> Sailor: "It may seem so, now keep going, ahhh"
> Sailor 2: "Hey man, more than 10 minutes already passed , it should be my turn now!"
> Sailor: "Okay okay, now girl suck this other guy after i cum, remember you lost the bet and now you have to serve us all, hehe"
> Wife: " (slurp, slurp) Ooo, okay... "
> Sailor 2: " And wash your mouth with rum before sucking my dick, i don't want to get a disease from this other dipshit"
> Sailor: "Hey, that shit is a myth..."
(Then more dialog happens, you see a simple sprite animation of wife giving head, untill you are very close to the action, and finally can see what is happening).