With all that said about my situation today, everyone has been telling me to be firm. In case something similar crops up in the near future, how do I go about extracting information when my wife will not give it up? Do I make her so livid that she screams "That's it! We're through" and/or storms out of the house with my son? Or, how would I convince her to let me go with them? I don't want to be so stubborn with my boundaries as to push her away.
Don't pressure or argue, just state your position and leave it at that. Don't try to control things that are outside of your control. If she absolutely refuses to co-operate there is little you can do to force her. For now focus on the boundaries you can enforce, which are things she demands of you.
Good call on the attorney, you need to protect yourself.
Spellfire aka Mike
"Women do not like controlling men. They respect and are attracted to men who control themselves. They ultimately are repelled by men who allow themselves to be controlled." -S&A