Boyfriend's Addiction to amphetamines

[Troubled-Girl]

I really need some advice here.I have been with my boyfriend for almost a year now and love him dearly.In all the time I have known him he has regularly taken speed, and has done for around 8 years.We've had a difficult relationship, many arguments, often over nothing, always caused by him.He's easily agitated and interprets things the wrong way, refuses to talk about things and never accepts responsibility.I used to think that i must have been to blame in some way for these rows and just couldnt see where i was going wrong.But not now, I've come to realise that the way he behaves is classic signs of amphetamine abuse.He is a great man, has a great job, but I am scared that he is going to ruin it all. He relies on this stuff to function normally, to get him through his normal day, this isn't a social thing.It is now affecting his whole life, could someone please advise me on what i can do, and how i can go about approaching him on this one?I am at my lowest point.x