Also could be a non BL series with an mxm side couple that also goes crazy
simple, every side couple ever rlly
https://www.mangago.zone/read-manga/from_points_of_three/
https://www.mangago.zone/read-manga/bbanana_scandal/ deleted but if you can find it somewhere else its totally worth it
https://www.mangago.zone/read-manga/my_suha/ toxic but interesting
https://www.mangago.zone/read-manga/highest_order/ a classic
https://www.mangago.zone/read-manga/akai_ito_no_shikkou_yuuyo/ side couple has its own sequel, you can find it in "author's other work", it's the first one
https://www.mangago.zone/read-manga/yakimochi_wa_kitsuneiro/ same here, this is the main. https://www.mangago.zone/read-manga/aimai_na_wolf/ this is the side couple
Something about side couples just hits me harder. Maybe it’s The way I have to scrounge the text for crumbs of their interactions gets me invested.