One thing you said resonated with me, and I hear it on this forum, and everywhere, over and over. She is blaming relapse on mental illness. That is something that happens over and over keeping loved ones feeling like they are locked down with this person. What came first, the chicken or the egg?? Mental illness or addiction?
Eventually you realize that only actions matter, and what came first does not matter.
I am glad you are not letting that anger overtake your life, it's quite easy to let that happen.
I send you and your children my thoughts and prayers.