Your problem from 10 years ago doesn’t define what is happening now. If it traumatizes you so much then work at a different school. Don’t bring in your problem to the students.
She’s literally seen what he’s done and how many girls he’s slept/ played with and yet she wants to be with him. The most basic things make her blush like cmon girl have your standards set high and keep your options open.
Your problem from 10 years ago doesn’t define what is happening now. If it traumatizes you so much then work at a different school. Don’t bring in your problem to the students.