Responses
this manhwa fits your description so much but instead it's the other way around, the blonde is the seme and black hair is the uke...
https://www.mangago.zone/read-manga/boss_bitch_baby/
bl manga where the uke is an ex host or playboy or womanizer or all three... i cant rlly remember much abt the seme but he locks the uke up in his house or smth.. uke was i think blonde, seme black hair. sorry for vague description