A lot, though not all, WSes seem to enjoy control and power without any consideration of fairness or kindness, particularly the men. It is very common for them to keep manipulating, basically pressing buttons or keeping others on a string even after separation. They are hooked on simply having an impact, whatever it is. So they do things that make it hard to move on. They seem difficult to understand because they switch from being extremely loving and repentant to threatening suicide to extreme rage. The jumping around does make sense when you realise they are just using different tactics to get the same goal, which is to have an impact and/or control over others. When they see the control slipping they escalate to the next tactic.
This might or might not apply here. Either way I think you need to just not respond to communication that isn't directly about logistics to do with the kids. Cut back to text message if you have to. And be prepared for the possibility of escalating tactics.
Maybe it is okay, maybe it will be okay.
BS, d-day Feb 2017, 16 mth affair.