Originally Posted by
Recovering2 
You won't hesitate to contact social services if there is a serious risk to your child? Your AGF drove drunk with him in the car. Is that not serious enough? It only gets more serious when she actually has a car accident.....pleeeeez don't wait for that.
You are not stuck in this mess. She is your GF, not your wife correct? You can still back out of the house, don't tie yourself to her any more than you are. Take that child and run for the hills. Get him to safety, and protect him. This is a progressive disease. She is already decompensating according to your post. However bad it is now, it's going to get worse. So the fact that it hasn't turned catastrophic "to date" doesn't mean anything. It's not her parents job to protect your son....it's your job. Read on here about the suffering adult children of alcoholics deal with throughout their lives from living with this chaos. He's 2, it's not too late to save him. You can not save her, but you can save him.
Ditto to everyone but especially this post from Recovering2. One unfortunate thing I have learned from talking with other spouses/families of recovering alcoholics is that many times everything is OK until the day when it just isn't & never will be again.... that it didn't feel like it was too late until it was TOO LATE.
Another helpful thing for you right now might be to document, document, document every single thing that you can that proves your son needs to stay in your custody. Separate your finances as much as possible & work on an emergency fund in case it becomes necessary. If you expect her to fight viciously then use your time wisely now to prepare in case it comes to that.
I'm not telling you to leave or that it's your only option, but I don't think there's anything wrong with taking precautions in the face of severe addiction. It sounds like she's very aware she has a problem but doesn't want to or isn't ready to take the steps necessary to live a sober life, which is her decision to make. You just have to decide if that is tolerable for you & your child.
I hope you keep reading, there is a wealth of information & shared experiences here at SR!