Step Daughter problems (need advise)

It almost does no good to charge her rent or anything like that when she does have a job because the wife just covers for her and is definately the enabler by letting her piss her money away when she is suppose to be saving for a car and her own place but its hard to save when you dont have a job and its no concern to try to find one. She goes on the computer and fills out one app and the wife thinks that thats good enough and she really trying. Its just a really bad situation and I'm about to my snapping point. Thats what it came to last time when I kicked her out and theres been no change since shes been back home again. Just puts a real strain on the marriage