My BW and the OW's BH keep in contact on occasion.
We were very close friends with the other couple before. Of course I now realize that is not really true is it?
In the beginning, I was concerned that my BW could be headed down the slippery slope with him but that was me placing my shit on her. I was also not fully aware of what the conversations were about.
Now, she tells me when they talk and what they talk about. Most of the time it is to keep an eye on me and the OW to ensure NC and of course I think this is great.
They do talk about the A sometimes and share information. My BW does not really want to know much about the A from him as she knows my view will be different from the OW. I was initially concerned that the OW would take revenge and feed lies about me. I know I hurt her as well. Her BH also found out (or at least got confirmation) from my BW.
I would say NC does not apply as long as the conversation is kept to sharing of information and helping to avoid NC between the APs. If the conversation turns to consoling one another then I think there is cause for concern.
What defines us is how well we rise after falling.