Back when my daughter was active in her addicition, I was obsessed with it and her. Looking back, the more time and energy I focused on her and her problems, the less I focused on my own. Rather convenient, eh.
Take the drugs out of this for a moment and ask yourself why it's been acceptable to you to stay in some sort of a relationship with someone who will not work, can't cope with life as it is, lies and steals from you and others.
I mean, what's in it for you? We codependents get hooked on being needed and feeling that we can control/cure other people. If all it took was love, none of us would be here.