I'm so sorry you find yourself in this position. Welcome to the board, we are very glad you found us.
The very best thing you can do right now is educate yourself about alcoholism so that you can make the best decision for yourself and your baby.
I promise you that he knows and understands how his drinking affects you and your relationship. Right now, that is not enough for him to change. Right now, he can accept the consequences of his choices.
You are not helpless. You can take care of yourself. First though, you need to know what you're dealing with when it comes to addiction. Until an addict decides that they have had enough, there is nothing you can do or say to make them stop. Cutting down is not really an option. Counseling with an active addict in denial is pretty useless.
There are a lot of "Sticky" posts at the top of this forum with a wealth of experience, strength, and hope. I am confident you will see your story reflected in those posts. The good news is, you are not alone.