R.K.'s manga / #step brothers(2)

Ch 3 Uke runs because that Blondie who slept with his step brother (non blood related) told him he was ruining his brother's life. Pretty sure big bro only slept with him because he didn't want to force himself on his bro when he was still underage/before he knew how he felt. Idk, or maybe the big bro didn't know he liked him romantically until after Uke ran away. (He called him kid when thinking about the flashback)