Need To Detach, But How?

[NASCARDaddy]

Okay, so the last two weeks have been all about detaching and I thought that I was doing pretty good. There were a few slips but over all I have done a pretty good job of not engaging with W. That was until this morning. This morning I contacted her to find out when I was supposed to take care of our kids this week so I could plan my schedule and she launched into an assault that turned into a nearly four hour long text fight. Because I am helping provide child care while I am off from school I still need to contact W to arrange schedules and she is defiantly try and push me into a confrontation because she is very angry right now, although she refuses to admit that she is. However I don't want to continue to fight with W so how do I continue to have contact with her and still not get sucked into her drama?