Thank you for the translations !
I'm still surprisingly really fond of this manga even if I wasn't really into the side pairs chapters, I just really love the relationship between Nagisa and Mashiro
She clearly state that their feelings were mutual, though. The issue she had was with physical intimacy. People don't tend to think there is "something wrong with them" because they're straight.
You do realize that he has no way to force her to take care of him if she doesn't want to, right? It's not a game anymore, and she's not railroded to the possible existing ending.