There this two manga that I can't seem to find for a year now and so I don't know will this be any better but here go.

The first manga is this old manga that came out before or at 2012. It isn't a
tankobon or doujinshi and there a english translation but I can't find
it, I do remember I once found it at hitomi. It have two adults who are
in a tent at a office builiding I think. Soon or later they have sex and
at the end they get married. It doesn't have netorare, rape, cheating,
loli, gyrau, incest or milf.

The second one is this english hentai manga from nhentai that I can't find. It starts off with the girl kidnapped and rape by a guy with bdsm stuff as a child but the cop arrives and rescue her with the guy arrested. The girl grew up as a high school girl now but felt something missing. Then the guy from before show up again and naturally rape her again but there a twist which is some male student show up and was watching them. I think the student guy is her boyfriend not sure but he ask for the guy help to rape her and then the male student have sex with her too. In the end the girl realizes she a slut now and love sex with the male student call in other students to have sex with her.