one of the guys could actually have a wife but he knows that she has been cheating on her and has always had a close teacher/student relationship with the girl and so is like and wants her
one couple could like be deadly serious and everything but she could be like possibly pregnant?? idk
one couple could be in the midst of idk, the head teacher or one of the students' friends finding out and so they are being blackmailed??
and then the other could just be like the girl is already in a relationship but the guy is a real jerk and so the guy is like a prince charming and everything and that's how they fall for one another??