Wow, I am outta here for a few days and come back to this! I am sorry to hear this news, although it is not surprising. And it sure explains a lot, right!? You sound good...so I am not going to suggest anything except that you punch your "best friend" in the face! Just kidding!!! I know this isn't funny, however, what else is there to do but laugh sometimes?
I think there is a time and place for confrontation...but if you are going to continue to DB, then it is not now. In my opinion, it is ok to subtly let your friend know you are onto them. Not sure how...maybe change brokers like you said. If they are communicating then this will certainly be passed on to her through him and combined with the fact that you are calm and collected, could send a message to W that you are moving forward with your life.
I am curious how much you shared with him about DB?? Did you do this in an attempt to help him with his divorce too? Does he confide in you about that?
Me:35 BF:36 Together 4.5 years lived together 2 years moved out 8-13 still "together" but not together. Confused. D11, D13 (from 1st marriage)