Don't talk to OW about anything-if she cared about what you thought she wouldn't be having an A with your H. She will probably think you are either lying or she can change your H.
I wouldn't tell OW's H about this place. It is your sanctuary and OW might get wind of it from her H.
Saffie's spot on here.
I have seen instances where the OW showed up here to get INTEL on what the LBS was doing to end their affair... the LBS had to leave the forum since all her plans were revealed to OW by posting here.
Not only was the LBS driven out of her marriage by this OW, but the OW drove her off of this forum as well...