L.N.
A.,
As so many of your other responses have said, there is no easy way to deal with this. There are so many emotions running high and unfortunately, no matter how much we try to leave our kids out of it, they are ultimately the ones caught in the center.
Currently going through this myself, it has been a long 2+ year battle, I have found that there are a few tips for survival.
One, have a good lawyer, a really, really good lawyer who you trust. If you don't have one I would HIGHLY recommend Kamie Hefner, she is amazing.
Two, be honest with you son. My son is only 5, but I have found being honest, in a very gentle manner, is the best medicine for those hard to answer questions.
Three, as hard as it may be, don't talk poorly about your ex to your son or in front of your son. We all need to vent, believe me, I do my fair share! Just make sure it is away from the listening ears of your son. Kids are so perceptive.
Four, don't stoop to his level. If he (your ex) starts to get ugly, raise his voice, whatever he chooses to do say calmly, "I will continue this conversation at another time when you are calmed down." or "I am hanging up the phone now." Etc. I have limited my communication with my ex to email and via the lawyers only. It really limits the chance of tempers flaring. If he is mean in the emails, have a really close friend or family member that you trust 'control' the email account and fill you in on the things that you need to know. Just remember he is angry at you for whatever reason, but he is also full of hot air.
Take care of yourself and take care of your son - let your lawyer take care of your ex.
Last, keep records of everything. It is a pain in the rear end, but you need to have all of your stuff in order when and if you end up in court. Emails, phone logs, late payments, etc.
Good luck and please, feel free to write to me anytime. I can COMPLETELY relate to what you are going through now. It is no fun.
Hang in there.
L.