Did it ever occur to you that your wife sees something about you that you don't see -- namely, that alcohol has you in its grip, and you can't free yourself from it on your own? Yes, you say you can stop any time you want, but if that's true, why don't you?
I also hope you'll ask yourself why she keeps getting after you, even if it irritates you. She does this because she loves you, and she knows that your life -- including your marriage -- is gradually being destroyed by alcohol. She loves you so much that she's even willing to endure your anger. Instead of being upset, you should be grateful for her love and concern. The Bible says, "Wounds from a friend can be trusted" (Proverbs 27:6).
Face honestly what alcohol has become to you: something you think is a friend, but in reality is an enemy. Then face your fears, swallow your pride and admit you need help for your problem. If you refuse, you may lose everything that's worthwhile -- even life itself. The Bible's warning about alcohol is true: "In the end it bites like a snake and poisons like a viper" (Proverbs 23:32).
Most of all, I urge you to turn to God for the help you need. Christ can do what alcohol will never do, by filling the empty places in your life and giving you a new reason for living. Turn to Him today.