Is it BL Motel ?
http://www.mangago.zone/read-manga/bl_motel/?MRdP
Err, not. I've read and watch Koisuro Boukun and also not Bl motel (im currently reading this one) to narrow it down, it's not a manhua or manhwa, it's a manga. And there this scene from that manga that I vividly remember, the uke just arrived in the house of his seme and he sit at the couch and they are are having an argument and the seme kinda neglecting the uke and siding to the uke's hated brother (which btw is also gay) gaaaah I really want t read it again.
I'm looking for yaoi manga where the uke hates his younger brother who is gay but ended up having a relationship with a guy who is someone older than him, I think the older guy is a teacher or a salary man. I hope you can help me find this