All of them who are with him, would probably stay with him, considering they don't exactly have much options.
- Ami, Maya, and Noriko likely already accepted that part of him.
- Ayane, Io, and Rin, would probably try to help him with his issues.
- Futaba, Haruka, Kirin, Maki, Makoto, Miku, Molly, Niki, Sana, Sara, The Tsukiokas, Uta, and Yasu would probably just look past it. (Maki might report him, but I'm not sure.)
- Nodoka would probably try to understand him mentally.
- Otoha might bond with him, considering she's potentially a shotacon and knows Sekai. Already tried to bond over being shitty people.
- Tsuneyo would probably just be even more wary of him than she already is. He's already a possible rapist in her mind.
- Wakana, Osako, and maybe Imani and Rika would probably report him though. (Not sure about how Rika may feel about this.)
Chika, I could see probably just ignoring it. With all the Chinami stuff Sensei can mention throughout the game, I wouldn't be all that surprised if Chika and Chinami are both somewhat aware of it already, and just try to ignore it, so that they can be happy.
Kaori and Nao-chan probably aren't going to care much. It'd definitely be a unique conversation..
Karin, Yuki, and Yumi are probably the only ones that might cut off all ties with Sensei that they can. Yuki is apparently protective of kids:
And I can't see her just being okay with this. Yumi cares a lot about Chinami and already has enough reason to hate Sensei. This might cross the line. Karin, is well, Karin.