I am not licensed in New York, you will get a more precise answer from an attorney licensed in that state.
Prescription abuse is epidemic in this country and I personally believe that the pharmaceutical companies have contributed to it by offering overly optimistic assessments of the effectiveness and addictiveness of their pain medications. However, the legal system does not yet recognize the role played by the pharmaceutical companies in this process.
In addition, I do not believe you have a cause of action, your husband is seeking out the pain medication, probably telling the physician about the great pain he is in, and the physician is prescribing based on your husband's statements. Pain is highly subjective, and treatment is based on symptoms reported by the patient.
As you and your husband have learned, addictions are incredibly difficult to beat. In your situation I would suggest that you seek out a program to provide you the support you need, al-anon comes immediately to mind.
If you really want to explore this, you should see an attorney in your area.
I am licensed in New Mexico and Pennsylvania, and therefore any discussion of issues related to other states must considered within that context. In addition, my comments are not intended to create a legal representation but merely to respond to the limited facts presented by the question. Any opinion herein is not meant as a precise statement of legal rights or as a recommendation of any particular course of action. A more complete legal review can be obtained through local counsel.
As my colleague suggests, it is very likely that your husband is reporting a legitimate need, such as extremen pain, to secure his prescriptions. You know that for someone to make the first steps to leaving addiction, the impetus has to come from within. I see no basis for a lawsuit, but you should consult with local counsel to see if there is some remedy. It seems likely that, unable to use one physician, your husband would see another, or even buy illegally.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.