I can’t save him. Why is it so hard to give up.

My boyfriend of six years has been battling addiction for over 20 years and he just got out of treatment for the hundredth time and decided to use and I just found out he has a UA from his probation officer today. He could go to prison for a while. I tried and tried and tried to tell him to please stop. I read about addiction and I know that I can’t control him but I thought maybe he just an influence. I’m just so sad and I feel bad. I want to scream and I want to yell. Underneath that disease he’s a good guy with a good heart who could do so much in this world I can do is cry.