I personally don't think that you should be discussing the details of your marriage with your D. That is an awful lot for a kid to handle. I know she is 20, but I have been in her shoes (my dad went through this when I was 21) and I was never told the details. Things were uncomfortable enough...and quite frankly, when they got back together...it took me much, much longer to forgive him about everything that he had done. Your kids are your kids, not your friends to confide in, not your counselor to seek advice from, and not to be used to try and fix the situation.
And telling them may just push your W further and further away.
My mother spoke with almost no one about her situation. When my father returned, she didn't have a lot of explaining to do as to why she took him back. She didn't have anyone judging her on her decision to take him back. It really was easier for her.
Scotty - I am just a rookie here and not experienced at all in any of this. But I did go through this before with my dad and learned some valuable lessons from my mom. I have told my family and two friends. That's it. Many others know - either through my H or through the kids at school (long story here), but not from me. To the best of my knowledge, only a couple know of his A. I don't discuss it with anyone. It is hard for me at times, but I come here to vent and it does help.
Anyway, I am relatively new and don't know if this is good advice or not...but it is what I would do.
May I ask where you are in PA? I do understand if you don't want to answer online.....