I definitely want there to be sex. Regarding the rape part though, a lot comes down to the way it's handled. The hentai approach you mention is pretty cringeworthy and way too common. At the same time, Stockholm Syndrome is a thing, and I think it plays very well to the male ego when they can magically win a woman over by sticking their cock in her. Not the first time as they'd clumsily do in hentai. But maybe then or a later time she has an orgasm despite herself and to her great dismay. Maybe at some point she shows up in Bobby's room to ask why he didn't rape her tonight, because she was hoping to get to bed early or had things to do.
It's not at all realistic really, and actually pretty offensive an idea to a lot of people. But so is incest and so much else in this game. And if done well, I think it could be kind of hot. That means not turning into love somehow or her turning into some sex-starved slut because of her sudden addiction to Bobby's cock. I see it more as a being resigned to their fate, and begrudgingly finding some pleasure in the sex.