Ok, first of all, when it became a problem for you and you put 2+2 together you spoke up. When you didn't see what was going on, how were you supposesd to say anything..it's that nameless something wrong until one day we realize that substances are behind the issues. So, let that guilt go.
Does not sound like things were perfect, but have instead been getting progressively worse as substance abuse does. It's ok to speak up when there is a problem -for YOU regardless if it is a problem for your spouse.
Drinking at work, in the car, verbally harrassing you, demanding beer when there is no money, inability to stop the behavior..definately enough to make ME speak up.
Please do go to alanon. They are not going to tell you to leave or stay in your marriage, but will help you figure out boundaries for yourself and your kiddos.