She is a straight up WAW, she tried for years and years, then whatever it is that you said to her during your Valentine's Day fight that the kids heard, snapped something inside her... re-read the DR chapter on the WAW... and what did you say to her?
Thing is, YOUR path is the same whether MLC or WAS...
The thing is this is probably the most likely scenario for most LBS's
One MLC kicks off a crisis or WA sich in the other person.
And either way you need to FIX the things that YOU can CONTROL.
