A book where the male protagonist is a perfectly fickle creature (someone completely swayed by their emotions and that don’t care about others, maybe a recreational drug user and promiscuous person that does it because they like it)

I want to read about how he interact with the world around him, and he doesn’t have to be the real protagonist but they have to talk about him like in paper town.
I feel like I read a lot about this type of characteristics but always in a female protagonist.

by Different-Adagio-774