Okay, I sit corrected, here's the update:
Tuesday (following minor problem with kid's scheduling) she said I needed to move out with one child. Lots of yelling and cursing.
Wednesday she said she needed to move out with the other child. Lots of yelling and cursing.
Thursday (this morning) from 6:00-8:00 am she said I needed to move out with one child. Lots of yelling and cursing.
At 8:01 it's like a switch turned on in her head (or off): she just comes out from blow-drying her hair and just says "I love you"
End of tirade. No cursing, no yelling. she drove me to work chatting happily all the way.
My feeling is that this is nothing to do with a relationship issue and everything to do with something that's happening with her. It's a pattern, it's been happening every 2-4 weeks. What the heck is going on? It's quite mystifying...