I would not expose it to her family. I was tempted to do that with my WW but ultimately chose not to and today, I'm glad I didn't.
Exposing it to OM's W is another story. Some members here (TxHubby) did expose the A and it worked in his favor. But other will say that those that do the exposing tend to not do as well. Exposing the A will enrage your W. It may stop the A but she could also choose to leave and be with him. Ultimately, you would want HER to choose to end the A and not force her to end it.
In my case, I kicked my W out of the house and I THOUGHT we were working on our M because I thought the A had stopped. I found out 2 1/2 months later that it was still going on so I filed for D and planned on exposing it at that time but OM confessed to his W. That ended the A and got my W to start coming out of the fog.
In my case, no one, including my W, can fault me for my behavior during our separation and her A. I was a saint. I was DB'ing and making myself a better man. I am proud of the way a behaved during that time. My W cannot say the same of her behavior.


Me: 48 y/o
W: 47 y/o
Together: > 20 yrs
BD: Dec '15, then S
2nd BD: Mar '16, then I filed for D
April '16: started piecing