You need to accept him for who he is. If he wants to change, he will. No amount of begging, pleading, crying, screaming, manipulating or threatening will make a blind bit of difference. If he wants to drink he will do, regardless of what you do or say.
You are not selfish at all for wanting a normal and peaceful life. Unfortunately peaceful and normal don't go hand in hand with living with an alcoholic.
Of course without booze he could be so much more, I think most alcoholics could. But you're right, you can't fix him and he's not without booze, he is who he is today, with booze.
What do you think you're supposed to do? How can you get a normal and peaceful life for you and your son?