In search of yaoi manga

So I kinda forgot the characters but like there's these two bros and protagonist bro sees his bro brought a guy (uke of the story) and like they are lovers. Protagonist bro is falling in love with uke. Though it's all good now it gets worse cause uke has someone chasing him, his half bro. Cause half bro is obsessed or soemthing and likes to bang uke. Protagonist bro's bro dies and uke gets taken captive by his half bro and for a few years he rapes him. Long story short protagonist bro and uke become a thing. Umm....I think it has a setting near the beach and there's a moon?