How or what can I do to prove my X has a drinking problem? What is considered alcoholism?

I am not an attorney, so this is a personal opinion, not a legal one…

Other than visitation and/or custody of children, I don’t think it is your concern after the divorce. If it is about visitation and/or custody I think you would have to prove endangerment, DUI or some other law being broken. “Drinking problem” is cause and effect and I think (again, a personal opinion) that after a divorce you can only concern yourself with effect - problems resulting from being impaired. I know a few people I would consider alcoholics because of the regularity with which they drink to the point of impairment, but they do it at home in a fairly responsible manner (don’t go anywhere afterwards and don’t have children to take care of). I know others who rarely drink to imairment, but the circumstances surrounding those times usually involve driving afterwards. I am not defending either behavior, just pointing out that I would be more concerned with problems resulting than whether or not there is an addiction driving it.

Alcoholism is a medical disorder which needs to be diagnosed by a medical professional. If you suspect that your ex has a drinking problem you can prove the same with examples of incidents of overindulgence, and dangerous behavior linked to the consumption of alcohol.