I think many viewers (including myself) were wondering what was the point of the new student-> bringing back that…
I am not sure how to answer it simply. But ML is quite calm and wise except when he is with the FL. He is quite jealous of the SML also. As he knew SML would start living in the teacher quarter, he also decided to live there. SML came to live there as his residence is far from the school and he is from Seoul. ML also resides in Seoul and grabbed the opportunity to stay at the teacher's quarter. I can't say the exact reason behind it, but he wants to stay close to the FL and impress her and her grandpa.
I think many viewers (including myself) were wondering what was the point of the new student-> bringing back that…
The FL and her grandpa had lost all their money and belongings, so now they live in the teacher's quarters. Both the SML and even the ML live there as part of their association with the school.
By the way, the proposal scene was perfect. Seok Jiwon and Yun Jiwon always have such great understanding when they are not behaving immaturely. The proposal scene was similar to the teenage proposal scene as even back then it was Yun Jiwon who proposed first.
I wonder how they will end the drama. Based on Yun Jiwon's teenage years and early twenties, she has the capabilities of a leader. Will she become a mayor or something like that?