I have talked to a lot of people that have owned a GX, and never found anyone that didn't love it. If they didn't have it anymore, they wish they did. I spent months talking my son (who has a Lexus phobia) into looking at one, and he loved it, too. He'll buy a 2015 when they come out. For my wife and me with no kids at home, the RX is close to perfect. It's a great size, extremely comfortable to drive, less expensive than the GX (and the truck), and the best road trip car I've ever driven.
If it were me (I love new cars!), I would remember that I'm in a win/win situation. I would let my wife keep her
car (still new, saves money, happy wife=BIG win), and get the GX in a year or 2 (another new car. Win). Maybe keep the RX after buying the GX and keep everyone happy (huge win)! It's only money, right?
I may look into a marriage counseling career!