I've managed to squeeze in some bb time this morning (H is sleeping) and decided to peek into your thread. I've seen you on so many other threads that I've been following over time.
Unfortunately, I have been unable to read all your threads, so my knowlege of your situation is limited to what I've been able to glean on this one.
What grabbed me about your particular situation, is the fact that the OW works for your H. I had to deal with that one myself. My H had a managerial position and hired a woman who became the OW.
In your summary, you listed all the positive changes your H was making, while repeatedly interjecting the fact that "the OW still works for him". This really stuck me in the heart. I relate to the misery this is obviously causing you.
Bear with me if you've already answered this, but does your H avoid conflict like it's the plague? Is he NORMALLY sensitive about hurting the feelings of people around him?