I know this is fiction, I'm just trying to analyze, not judge or anything but

I'm conflicted, because so far he's never explicitly said no to Yakumo/stalker, we haven't seen when all the sex part began and he's expressed he's doing it out of his own free will and enjoys it, but at the same time it can be all due to his own self esteem and manipulation or him being a yes man, I want to see how it progresses