There's no explaining, nor is there likely going to be any end to the emotional chaos. Prior to physically separating ourselves, I experienced similar instances of over reacting from a once loving person.
There was this deep need for independence in every sense of the word, and of course nothing I did was right. While suffering a stiff and painful back she could drop a pencil and heaven forbid I try to pick it up or offer any kind of assistance - ever. Any such action would immediately and regularly result in an outburst of anger filled with demands that I stop trying to help, in any way. I think we've seen this as part of how MLCers respond to their mix of guilt and resentment.
When they want you out of their life, your presence is probably percieved as the single greatest disturbance in their universe. No act of kindness is appreciated. "No Mercy" is their battle cry, even when you sense no reason to bear arms.
As impossible as it is to understand, overlook, or avoid taking personal ... let it go. If the unexplained interactions between the two of you are affecting the kids, it could be worth trying to discuss a "script" for morning and evening duties where the kids are involved. Think of discussing this with your IC. Wouldn't it be great if you could both agree on some method for declaring a mutual time out when things don't seem to following the script? Maybe a way to "step" through situation resolution along predetermined lines. (No Winners - No Losers ... just a get it done for the kids outline)
What would trigger her anger most, not sticking to a plan, or not having one she feels part of? Could the IC suggest any way to mitigate her overwhelming need to control and punish you? She can't and won't try to control her sense of resentment toward you for things she can't even explain. It is just who she is now, and will probably always be. You need some mutual rules of engagement - and disengagement. A time machine, Genie bottle, and fallout shelter probably wouldn't hurt either.
