Peo,
You are not alone. You can post and talk to us here at anytime. There are a lot of caring people here that have been though the same things that you are going through and can help.
Right now you need to look after you and your son. You need to make sure you two are taken care of first.
It sounds like your ABF is only only looking after himself and the alcohol. It's sad that he values that more then a great wife and beautiful son. Even if he cared a little he would not be blocking you out of your life completely like you said. He needs to fix himself before he can truly love again.
Just know you are strong and can get through this. You deserve joy in your heart and life. Look after your child and see the joy he brings to you. we are here for you. Post us anytime.