Be very careful about using any advice on this board. In my opinion, a lot of the people offering it here are in serious denial. They are so focused on "DivorceBusting" that they lose sight of reality, and when they start giving advice it's almost as if they want you to make the same mistakes they've made and suck you down the same hole so they'll have company. I doubt that endless analysis and documentation of your situation on these boards will help you. So, what would I do if I were you? I would:
#1 Read Michele's books carefully and re-read, several times, the sections that talk about affairs.
#4 Go to couple's crisis counseling with your wife.
#5 Go to counseling on your own.
#6 Talk to the best family law attorney you can find, NOW, not later.
## 1 through 5 are obvious, but why #6? Because you can't even begin to address this situation intelligently if you don't know all the things in play here, and, unless you're an attorney, trust me, you have no clue what you may face in divorce court.
There are things you need to know now to protect yourself and your kids if your marriage doesn't rise phoenix-like from this burning mess.
Michele's books don't focus on this aspect of the situation and appropriately so, but one problem I think I see over and over on these boards is that people blindly focus on her methods and don't realize that they should, at the same time, be protecting themselves and their kids through proper consultations with family law attorneys along the way.
You're situation is particularly complicated because if your W's baby turns out to be the OM's, then he will probably have various rights and responsibilities that you need to know about, too.