UPDATE 8/21/11 My wife sent me this response to arranging for our son's trip:
"Alamo,
Saturday 9/10 sounds excellent. You can go ahead and purchase a round trip ticket for yourself and then a one way for E to Spartanburg. I know Southwest allows for one way tickets. I need to purchase my return flight one way with E of course. Then that will take care of the splitting E's fares. I was also planning to fly back with E a few days later than originally anticipated. My brother Cody is being deployed overseas and I'd like to take E to see him off and meet his new baby cousin if that's alright.
Wife"
Also, I'm not sure what to respond to/proceed with my wife's refusal to pay for her usual monthly items, such as daycare, toll, etc. I'm thinking that I should send her something like "So does that mean you are not going to pay for these things?", but then keep sending her the bills regardless. At the end of the day, the courts might find this information useful.