help me find this manga

help !

Hi! I’ve been trying to find a manga I read years ago, but I completely forgot the title. I believe it was an early 2010s-ish shoujo/high-school manga. I’m hoping someone recognizes it!
Here’s everything I remember:

The FL initially had a crush on one of the boys in the group.

This boy had **black hair**, he was the most popular boy was quiet, and kinda depressed. I vaguely remember his family being wealthy/rich, and his parents being very hard on him.

The FL was quite **protective of him** and tried to help/protect him.

However, this boy was in love with an **older woman** whom he had known since he was very young.

She was **older than all of the main characters**. She had originally been a high-school student when the boy knew her as a child. i remember her not being conventionally pretty

When the main characters were older/high-school age, this woman became **a teacher at their high school**, alongside the rest of the cast.

The black-haired boy eventually **ends up with this older woman/teacher**.

There was another boy in the friend group who was the black-haired boy's **childhood friend/best friend**.

This second boy had **lighter-coloured hair** (I think light brown/blond-ish).

He was initially **rude/cold toward the FL**, seemingly because he wanted to protect his childhood friend and knew about the FL's feelings for him / his feelings for the older woman.

Eventually, the FL and this lighter-haired boy become the **main couple**.

There were **other couples within the friend group** as well, and their relationships were developed throughout the manga.

I remember the manga having a proper **epilogue/future ending** where everyone is older, around college/young-adult age.

The most distinctive thing I remember about the ending is that the **main couple are living together in a house/apartment**, and the other couples/friends are all together at their house.

The final/epilogue chapters basically wrapped up the romantic storylines of the whole group.

Unfortunately, I don't remember the FL's hair colour or any character names

thats it! help me out