I didn't answer your question about what to do regarding her shutting herself off in room with computer. As said before, I believe she has found a new EA or the old one is still active. Whatever the case, this is a display of disrespect toward you as her H. I believe you need to set a boundary in place. I don't think you were ready for that when you first came to the board, but I think you are now.
You say, "When you shut yourself off alone with the computer and/or stay up until the early hours in the morning b/c of your computer activity, it makes me feel very disrespected as your H. We have discussed this before. I have decided that I will not tolerate being disrespected in my own home. if you continue this behavior, I will __________________ "(state the consequences).
Don't allow her to interrupt you before you finish.
I don't think any exposure will do the trick this time. If it is the same man, she simply went deeper undercover with the EA so nobody at work would suspect. You need to think of a stiff consequences for her. Something that would cause her to suffer if she continued her computer activity. If it is not stiff enough, it won't work. It must be something that will cause her to make a life long decision. This has gone on long enough. Time to draw the line in the sand.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!