I've been reading along (for some time now!). All I can really say is your W sounds exhausting. She does sound smart, that I will give her, but I wouldn't be so sure her manipulation is not as planned as you think.
This has been going on for a very long time in some form or the other. I do admire the the love you have for her and your desire to do right by your children. Eventually though something is going to have to give. Your W is smart as long as you buy into her idea of "smart". Once you stop doing that she tends to act (as per your description) quite dumb.
Think about it - how could ANYBODY in the RIGHT MIND even say out loud to a spouse they cheated on... "well doll, I didn't realize it would be a problem to swap music files with the man I traveled around the world for to have a torrid affair with" COME ON LADY! She *thought* though she could use her "tools" (which are impressive LOL) to somehow convince you she didn't understand. Please.
I can't say what is right about dating or not dating but I do think you bring up a good point... once all this chase business is part of the past will she be content with a "regular R"?