Two things have occured to me reading this posdt. First, I honestly believe your wife has an abuse problem and wants very much for you to know about it. She is leaving clues all over the place, and usually that signals that the person with a problem wants someone to help , but does not know how to ask.
Second--I believe that almost every state has a program run thru the State Board of Nursing for addicted professionals. If she contacts this program, she will be steered into treatment, which is desperately needs, and if she completes it, will not lose her license, tho she will be restricted for a while.
If you can, you must confront her about this, very matter-of-factly, after you research what help is available thru the nursing Board. If necessary, make the arrangements and use the intervention approach. It s important that you do not ask if she is using, or ask if she has a problem, or become argumentative. You need to state, factually, that you know of her problem and you want to work with her to solve it. I would be willing to bet she will be relieved that you are acknowledging her problem and are willing to help her without judging or blaming.
I hope you will act on this immediatley, because an impaired nurse is dangerous not only to herself but to her patients. And sooner or later-probably sooner--her co-workers or supervisor will become aware of this. If she takes the first steps voluntarily, she will feel more empowered and will not risk losing everything.
Please let us know what happens--this could be any of us.