Yep been there done that. I don't think I called my W anything as nice as 'pig'. I believe the words I used rhymed with 'door', 'punt', 'pitch'...things like that.
The thing is that I found a note in my W's car when I was cleaning it, professing her love for her boss, he was her soulmate, etc. blah blah blah. Then when I confronted her with it, she told me "how dare you clean my car!" It's so laughable now.
Your W is in the same place. There next phase is that your W will either:
1) do a 180 and apologize, says she was "lost", etc.
or
2) become the most evil person you have ever seen. Blaming you for EVERYTHING from how you hurt her to you make the sun not rise at the right time.
The worst is yet to come. Stay steady and don't let your emotions get the best of you. You still have to be nice to her for your boys. Always remember that. You cannot disrespect her in front of your kids.
Which leads me to the DNA test. IF you subject your son to this, what difference would it make? Do you want your son to live with the idea that you are not his father maybe? Is that going to make you love him any less? Is this going to destroy their idea of their mom?
Take these things into consideration. I know it's not going to make you love your kids any less, but think of how they are going to be with this knowledge in the future. If you were your son in question and your dad and mom were in the sitch you are in now, how would you feel? Worthless because you're a product of an affair? A bastard child? Take all that and think about it.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.