It may help you to read the first few chapters of the AA Big Book online:
Big Book Online Fourth Edition. The description of alcoholism may help you really get that alcoholism is a mental craving beyond the control of the alcoholic which causes the alcoholic to drink against his will.
If you do not fully surrender to this cold, hard fact of his addiction, you will be shocked, surprised, devastated, and broken again and again in this relationship.
And you may be a person of enough backbone to clean yourself up after the wreckage he creates in your life and move on.
But as someone who once had a little seven year old boy in the house of an alcoholic man, I can tell you from the bottom of my heart that your child will NOT have the backbone and will NOT get over the damage an alcoholic does to his fragile, defenseless psyche.
Please listen to me. I do not usually urge people to take action they are not yet ready to take.
But when children are involved, we here cannot afford to mince words.
Your son is in grave danger.
Live separately from this man, date him if you wish, but AWAY from your son, all dates OUT OF THE HOUSE AND AWAY. You may say to yourself that if the man is drunk, that's when you'll bar the door. But alcoholics say vicious things to people whether apparently drunk or not because they are always in either one of two states: DRUNK or CRAVING. And it takes alcohol 48 hours to completely metabolize out of the body, and I very much doubt if the man ever goes that long without a drink. He is always drunk.
If you want to keep him, then do it away from your child.