Hi, I'd like to help you with your question.
Your wife is probably fearful that you will end up like her family. It is a normal fear for her. She was exposed to people who used alcohol and put drinking above all else in life, including family and health. To drink to the point of needing a transplant is serious alcoholism. And then to ask a relative, a victim of your drinking behavior, to sacrifice part of herself to you is making that relative a victim twice over. So your wife is fearful of alcohol and all the damage it has done in her life.
Although her fear is normal for her, it is not for you. You have seen the damage it did to your wife and her family, but you did not live with it until now. So to you, alcohol has a possibility to do damage but in your life, it is more controlled and you have more control. And you are not a direct victim of it's consequences, although you care deeply about your wife and her situation.
The balance here is to understand your wife's point of view while considering your own. There are some options to consider. One, you could stop drinking all together. How you would feel about that is the biggest factor to consider. Would you be ok with that or would you feel resentful?
Two, you could continue to drink but modify how much you drink. Make a deal with your wife so she feels she has some control over the amount you use. You also need to consider how you would feel about this, but it does offer the best balance of control and choice.
Three, you could keep drinking like you do now. The consequences of doing so you already know.
You could also seek counseling with your wife to talk this out. Having a third person who is neutral involved helps you both come to an agreement and deal with all the feelings involved so you can be settled with what you decide. To find a therapist, talk with your doctor for a referral. Or if you attend church, your pastor could help. You can also search on line at http://therapists.psychologytoday.com/rms/ (look at the bottom for a link to Canadian therapists).
It is good that you care for your wife and how she feels. And you understand the effects of drinking too much. You seem very insightful about how much you use as well. All of these are good points in your favor and will help you work this out so both you and your wife are happy with the results.
I hope this has helped you,