How Can I Make Him Stop Without Losing Him?

My man's been doin cocaine...through his veins. ive been with him for 4 1/2 months and i knew he did it but i thought i just blew a line here n there for fun not as a problem. about a month after i was with him he told me but i couldnt just leave him.now he only does it as little as once up to every 3 weeks...well not now because he is in jail for a while for probation crap.when he gets out of jail i want him to be ALL done with it but if he doesnt stop i know ill be in to deep to just throw him away. I just dont know what to do!
dear tata,

i sympathize with you and your situation. i've been dating a guy for a couple of months. he smokes pot daily. he used cocaine for years and quit two years ago- at least that is what he told me. his behavior has been sort of strange though. he leaves his apartment late at night. tells me he's going to see someone about a car or to give someone keys. he's a mechanic. it's just odd. he has told me of many of his friends doing drugs. he just hasn't told me that it's him. maybe he isn't. my thing is i don't even like the fact that he's addicted to pot. i am trying to quit smoking cigarettes and have been on and off since april.. after smoking regularly for 15 plus years. i'm trying to take care of myself, at least wanting to. my instincts have been telling me that this guy is no good for me. it would be another codependent relationship. i've had that before. i have more knowledge now. i just have to pray that i will do the right thing. i pray that you too will do the right thing for you. it isn't cruel to leave an addict. you don't owe him anything. it's almost cruel to yourself to stay and almost cruel to stay with him and enable him by continuing to love him and need him, etc.. good luck and do the right things to help you to get, to be, and to stay strong.