Please help me, I almost went thru the 948 pages of the age gap tag for this one

So I'm only for a manga, I only remember the rough story
1:age gap
2: Older one lives at young's one house (its kind of an inn so he's kinda a tenant)
3: During the backstory we learn the older one has loved the youngest since he was a small child (kinda pedo I admit but he doesn't touch or flirt with him at that age)
4: The older has a job where he must travel??? I thought he was a novelist? Maybe not
5: Main story: we'll call oldest "O" and youngest "Y"
So Y just reached adulthood, he's now 18, and he wants to confess his love to the his father's friend (tenant "O") .. he's had a crush since highschool, at first he gets rejected but he eventually gets into a relationship ..