Leane of Legitimate Crown 2 is exactly that. But combat is really slow and annoying. The build-up is done well and takes a while before any scenes. I played on easy and it was still hard as hell imo. Most games that only allow NTR when you lose combat suck ass, and I don't care for doing that. But in this game, if you win, while the girls won't be taken by the enemy generals, you have another aspect of keeping the king happy by building him harems and letting him waste your war funds. If you don't do any of that the king sends guys to take the girls and put them in his harem.
In fact 2 of the girls in the main route get got no matter what you do(unless I just missed somthin), the feisty knight and the girl that saved you and housed you for several months. You go off to fight off an invasion and come back to the king just banging the hell out of them. The king being a guy they both hated for the several hours you played up until he becomes king. Basically, the invsionn comes and you send the girls to the capital to be safe, and in the several month your out fighting they get corrupted by the king.
Then the other girls who are all your generals will get taken to the king unless you actively stop it. The only big downside to this game is the dogshit combat. The game would be so much better if instead of turnbased ultra slow garbage combat it was just the game of Risk rules. COmbat you capture cities and such, but every cutscene event it resorts your units to the event area and you lose a ton of places, kind was pissin me off.
Honestly, I almost stopped, but that first NTR event hit perfectly, cause it really built up the repor with the girls and just to have this POS snatch them away while you were saving the kingdom.(You come back and find out he made himself King, and was dicking your girl) Not to mention placing the old kings wife who was a prim and propor lady as head of his harem, lol.
The version I played crashed at the first NTR event if that happens there is a patch, it happens if the king decides to bang a certain girl.