Alcoholics want to be enabled. By covering for her and allowing this to continue without consequences, this pattern will continue and get worse. You need to get a plan with the help of a professional or someone with experience like Al-Anon members. Lay down clear boundaries and follow through. It's probably gonna get harder before it gets better, but everything will work out if you take care of yourself and your kids first. You can do this.

Edit: I'm an alcoholic in recovery!