You may be correct. I only know what I have been exposed to. My own alcoholism, 4 inpatient treatment centers and many AA meetings are the basis of most of my knowledge.
If your Grandparents from Ireland drank, they may have been normal people who drank. Normal people (non-alcoholics,commonly called 'normies') cannot give alcoholic genes to their children. However, alcoholism seems to follow a family around, like your relationship with your ex-husband. Your initial attraction to him does not automatically make you an alcoholic though.
The way it seems to make the most sense is, "if you have a problem with alcohol, alcohol is a problem for you." The original question posed on this thread is asked by a young man whos girlfriend is admittedly having a hard time with alcohol. I told him that his girlfriend is "probably" and alcoholic. She may not be. Some alcohol abusers are just normies who drink to escape from feelings they do not like.
I think its different with drugs. Drugs are addicting in and of themselves, some more than others. Alcohol is not physically addicting unless the person is born with the body of an alcoholic. There is a distinct difference in the way about 10% of the American and Northern Europeans process alcohol.
What is interesting is that people of Jewish descent have a rate of alcoholism of about 1%. Native Americans experience it at a rate of 80-90%. What's the difference? Alcohol has been part of Jewish culture for more than 2000 years. Native Americans have only been exposed to it for about 300 years. What happened to the Jewish people 2500+ years ago? Did they die of alcoholism the way Native Americans are dying of it today?
Alcohol kills more people in one large American city in a week than die of all other drugs combined in the entire Nation, in a year. Even if you are not biologically predisposed to have trouble with it, it touches all of our lives.