Is it fair for my boyfriend to ask me to stop drinking? I don`t drink often or heavily.

My boyfriend was recently diagnosed with a disease that may be perpetuated by drinking. Since I have known him, just over a year, he has not been a big drinker but now he has given it up altogether. I would never pressure him to drink and fully support his decision to stop. However, he is now asking me to stop drinking and saying that would be the best way for me to support him. I have thought a great deal about his request and can`t come to terms with it and completely give up drinking just because he wants me to. I do not have a drinking problem. I drink responsibly and in moderation. But I do enjoy sharing a beer with my friends or going out for a drink every now and then. I have never been told that I change when drinking or has anyone accused me of being a bad drunk, and I am rarely drunk. He sees my refusal to stop drinking completely as a betrayal. What should I do?