What he was when you first met is in the past - that person may or may not surface again but that is in the future and is an illusion you hold onto. All that matters is what he is today and today he is an addict in active addiction. If you dont let go this is going to spin out of control quickly and you will be caught in the cross-fire. just take a step back and out of his circle for a while. you dont have to make decisions on ending it or staying with it just choose to stay out while its this crazy.