Any time you want to talk privately please do so. Some times public talk is just too vulnerable. PM anyone you feel comfortable talking to. I can't guarantee that people will respond, but if they don't try someone else. We are all understanding and willing to listen... most of us here have been through some shit with this stuff or at least are in a similar boat.
I can understand that at some point philosophizing and theorizing get tiring, but remember she is starting out... maybe directing her to some useful sites and books (there is a "book recommendation" sticky) would help. There is also a lot her on "mono/poly" relationships if that will help her understand that she is also not alone. It sounds like she might need some catching up...
As for your son. I'd just tell mine that I love lots of people and that sometimes that can be hard to navigate in a marriage... end of story. The rest isn't his business and really he just wants to know that he is loved and that his place in the family is secure.
Anyone want to be friends on Facebook?
Send me your name via PM