I should check on that, Nut. I guess I need to talk to an attorney.
Yes Yes Yes! Just because you consult an attorney does not mean that you have to take any action--it will be your call. Having said that, no principled and considered action that you take at this point will drive her any closer to the dbag. She's already there.
You need to be prepared for the worst--an ugly divorce and custody battle. If you know ahead of time what her options are and how to counter them, then it won't throw you for an emotional loop when she threatens you with them. You'll be able to look her right in the eye and coolly say "you will do what you need to do." That's confidence and that's attractive.
As far as exposing the affair to the superiors at work, that could cut both ways. It might make the affair more difficult to conduct, but you run the risk of looking vengeful. Also if your wife loses her job, you will be even more on the hook for spousal support. She would also have less to contribute to the upkeep of your children. You should run this by your attorney before taking any action. You might want to reflect on your reasons for doing it as well. 10 years from now when your kids talk to you about how you handled this situation, you'll want to be able to look them in the eye.