WARNING: LONG POST ***I don't know what to do anymore....

My fiancé is an addict. He is addicted to coke and I don't know how else to help him. I am beginning to realize when someone is down that road there's no turning anywhere else unless THEY want to...I'm hurt and desperately want to fix things. I truly am in love with my man and wouldn't want to see him go though bad shit. Now before you judge me I knew he did drugs when I met him. But I promised him that I would help him get right not only to be the husband he's always wanted to be but to finally be a father to his 2 girls. He also asked me to help him. So I helped him. I stayed through all the bs. Even devolved a cordial relationship with the mother of his child. He went from doing drugs everyday 24/7 to one day a week after I met him. I was so proud of him and he was so proud of himself. Now 2 years in and it seems like he's going back to the same shit he was in before I came into his life. And I don't know what else to do. I understand you can't keep an addict away from the one thing he's addicted to but I had the mentality that he would see how much of a value his life and his kids are and that, that would somehow trigger his mind to stop the bs. Just recently I called his phone because it was 5 in the morning and he wasn't home and he didn't answer but his pocket did. I heard what I was dreading to hear. To sum up what I heard he's gone from coke to crack now.... I've dedicated so much of my time and love into this man somebody out there please tell me there's some kind of hope???!!!!! It kills me to see the man I love do this to his life when he has so much to live for but doesn't see It.