I think it was the Uke parents passed away at a young age and ends up living at relatives or family friend. During that time uke closed himself off and the The seme was also there since they were children protected him and cared for uke.
there was Scene (flash back?)
where both as a child, seme stood infront of uke's room arms out as if stopping the adults going in, when the uke shut himself curled up alone in dark room.
It was seme who brought uke out. Possible uke also is relies on seme

not sure but it could have been a oneshot in a volume or was it part of a series

Edit. Found it
https://www.mangaupdates.com/series.html?id=2223