I am currently going with the ignore him approach. I went with a short discussion on Friday thanking her for letting me know about the phone call. I also mentioned that it was good to talk about it even though it was difficult on both of us.
We haven't talked about him since. I got the feeling that she knew what was right and what needed to happen. At one point she got a little defensive:
... W: "I didn't call him." (a little frustrated) M: "I'm not blaming you. I'm just stating it is hard on both of us." W: "Yes. I know. I think he got the message this time that I don't want to talk to him anymore." ...
This statement makes me think that she believes this has concluded. I will wait and see how his next attempt of contact plays out.
