
I feel like the girl will end up jealous bc everyone will stop paying attention to her and start focusing on the guy

Sei is the protagonist of "Seijo no Maryoku wa Bannou desu". Ill leave the link here in case you guys want to read it(@^◡^)
http://www.mangago.zone/read-manga/seijo_no_maryoku_wa_bannou_desu/

She LITERALLY just explained how terrible she would feel if she was the wife and now she’s trying to do it again????????

This is where a smart person should start avoiding him. If you can't handle a temptation being around, run away whenever you see it. Change departments or companies, or at least avoid going to the smoke room when you know he'll be there. If you need to tell him why you're avoiding him, do it, but hanging around him is just going to cause more harm.
I don’t get why but reading this gives me such anxiety by the way the teacher gets treated like I hope it gets better