Koi...??

Can you help me find a yaoi manga.
It is about a uke mc, a boy whose mother want to remarry to the seme 's father. So the mc and seme are kinda brother but not blood rlated. They left the father and mother together for "meet" i dk lol. to an arcade where the seme fallen for the uke. After living together in the same roof, the uke saw the seme on top of some boy on seme's bed. Uke fond out by the seme, kinda awkward. The mc left home and live at dorm and the seme got his own house/ apartment. Ah, i dunno the rest but they got together at last.