I agree with you Brooks - I didn't see this move as something to hold against John. He and Candace did have a little conversation about it. I would have been less impressed if Candace had stayed. She's already played the game, it's his turn.
Someone else (sorry, don't recall who or in what thread) put it that each spouse in a way sacrificed so that their loved one could have the full Survivor experience--camp building, competitions, etc. If you take gender out of it that's the parallel. Meanwhile the experienced spouse has the less fun experience of RI.
His wife has had two shots at this game and hasn't done that well. It probably was a good thing for him to stay over her!