Hello, I'm looking a shoujo/romance/school life manga that I read before but I forgot what its about. I suddenly remembered the story of its side character and its really bugging me not remembering where they are from.

So what I remember is:
- Theres a stepbrother of around the same age in the series.
- Pretty sure the older brother is a friend of the hero, while the younger brother likes the heroine (I think).
- The relationship between the two brother is not too good. The younger brother dislikes his mother's remarriage because it makes him feels lonely. The older brother keep trying to approach the younger brother, wanting him to feels like having a real brother only to be thought as a nuisance.
- It is later revealed that the brother is actually lonely too. After accidentally hearing the younger brother's monologue right after their parent's marriage, he realized that he is not alone and his new younger brother is actually in the same situation as him. This makes him wants to get along better with the younger brother.
- The brothers appears quite often in the series. but usually not together. I remember they are present in the summer festival chapter of the manga. And the hero and heroine also once goes to their house to study.
- As the story progress, the brothers' relationship gets better when the younger brother finally understood his older brother's feeling.
- It is also revealed that their parents are now pregnant and both of them are happy about getting a new sibling.

I know its weird to find a manga using its side character. But this is all that I can remember. If anyone have heard of this brothers, please tell me. It will really help.
P/S: recommending random good shoujo manga helps too, because Im pretty sure this series is pretty well known. Maybe that can be what im looking for.