My H's OW 'outed' their A to me on FB. She thought I would race to an attorney for a divorce. First, I got this invitation to be a friend from someone I didn't know, and innocently accepted. Was treated to 34 pics of her and my H. Canceled FB account immedicately.
H, who always made fun of FB, texting, etc., now is right in the thick of things, FB acct and all.