https://www.mangago.zone/read-manga/sand_castle/
At first you feel bad for the black haired guy but then you feel bad for the light haired one until you realize they're both horrible and deserve the worst things in life. (one grew up in a rich family not knowing love because his parents loved each other more than him so he "tests" the black haired guy's love by being tempermental, bitchy and mean to him to see if he sticks around) (black haired guy likes guys who aren't interested in him until they like him and are obsessed with him before dumping them for being too "clingy" and "attached")
need to see a toxic ass couple being equally horrible to each other
thanks