Re-read your post. Then read it again and pretend you're a stranger reading your story for the first time.
Many would have left after the first few paragraphs, let alone the whole history. You feel guilty because you've had many years of being told it's your fault, which is standard behavior because it keeps the enabler focused on themselves and the drinker can be left alone for a while to get back to what's important...drinking.
Your kids are now confused and have been exposed to an alcoholic mother and her chaos for most of their lives. They need help and focus to make sure they don't repeat this pattern in their own lives.
Not your fault one bit. When you feel guilty, try to remember that this gives your children a chance to have a better life.
Sending you a hug.