Yeah that whole ... what do I call you thing during this actually made me chuckle more than anything ... seeing how uncomfortable she was in certain circles concerning me. At S's school it was always "My husband blah blah" ... but in other circles I got "my Ex" .... was like when it was better for her to be married she could be married, but when she needed to be single she was single .. Cake anyone?
I also find it peculiar that after your W stammers and gets off the phone she is all about letting you know about the girlfriends and girls night out stuff. Most likely falling in line with the MLC pattern that we become the authority figure, and they some hoe need us to know there is "nothing out of the ordinary going on here dad .. I promise."
Regardless you handled it like a champ ... well done.