I remember the first time my husband tried to get clean, he told me he just needed to find something positive that gave him the same feeling cocaine did. His second attempt at getting clean he realized this was impossible, and focuses on being the best man he can be.
The drug use meets a need, sounds like your boyfriend is trying to meet that need in way that he doesn't think will hurt anyone. Noone ever got arrested for playing video games right? But he doesn't see beyond that.
Recovery is a process. And it's hard, and it doesn't always stick.