A couple of commonalities that I caught that are similar to my WAW. One is that you noted that she did not seem as angry on your last phone call. That has been a good thing in my situation as it has opened the door for me to listen to her at the times when she is ready to talk. But remember, it must be her who initiates the talk, but that will give you the opportunity to validate her feelings.
Sandi's description above actually describes my wife very closely as well. I do not have any evidence of my wife having a PA, but we are separated (and divorce has been filed) and my wife is on facebook quite a bit, so as far as an emotional affair, I have no real idea. My wife has been a Christian for many many years, but made a comment to me one time that she feels like something is just pulling on her heart to experience more of life.
My wife knows to guard her heart, the heart is deceitful, etc, but when emotion takes over it's not easy (see Cain and Abel).
My wife will talk to me once in a while when I see her and we've had some discussions about some things we have not talked about before. For instance, one time she told me about something I did that she did not like. I asked her the simple question of how it made her feel when I did that and talked for quite a while.
If you are presented with an opportunity like I've had, listen to her, validate her feelings, and do not get defensive. It is always hard to do when your spouse is getting this stuff out, but in my case it seemed she had kept it bottled up for years.
Do I know if my marriage will work out? No, I don't. But I can tell you that my wife has told that she sees we are talking in ways that we have not before.
