Hey Ellie:
I don't know much about P90X, but I have one of Tony Hortons 10 Minute Trainer series, and can only handle the guy for so long... although, have heard you either Love him or Hate him... Guess the program you choose will have to depend on whether or not he would continue doing the workouts when he travels, therefore, needing something that requires using equipment that is protable and compact... in defense of the 10 MT series, they do not require anything more than a tube, door attachment and a door... the rest is all up to you! I'll PM you about this... maybe you would like to try it... I don't use it...
My DH is a TM fanatic... but I wish he would branch out a bit (so I can get a walk in on the dumb thing every once in awhile)! He has super "runners" legs (you can read that as 'lean white chicken legs' in that description! LOL) but would never want to discourage him, because at 50 years old (in 20 days) he looks damn good! Yet, he refuses to do any upper body or core work.. pokes fun at me for all the strength DVD's, weights, etc... that I have gotten into since joining the Cathe scene in August... give me a few more months with Cathe and STS and watch out... I could take him!
I wish that DH would consider doing STS with me... There are several buff guys grunting along with the Cathe regular crew, so maybe your DH will feel like it's more a unisex workout rather than just a bunch of buff chicks (sorry Jerry

) I guess it would be hard to do since he is on the road so much unless he stays or has access to a DVD player and weights and other equipment on a regular basis... I know how crappy I ate and how hard it was to exercise when I was gone for weeks at a time this past summer and fall...
not much help, but wanted to tell you that I am there with ya babe!