As usual your wife is right! Wall mounting flat panel TVs is the best and safest option. There are a significant number of serious injuries annually from not wall mounting TVs.
CEDIA are correct in that the optimal height for comfortable TV watching is to have the bottom of the TV around 30" from the floor.
So that means we all face your dilemma, unless we have an acoustically transparent projector screen. So for those of us using panel TVs it forces a compromise.
Now the optimal height for a tweeter is around 36" which would put the speaker right over the TV screen.
Putting the speaker below the screen in my view is only viable if the viewing distance is short, and a disaster if there is row seating, as there is poor room coverage. In addition it exacerbates floor reflections contributing to poor dialog intelligibility.
So that leaves the option of going above the TV, which in practice is most often the best solution.
This is my solution, bottom of TV is 27" from the floor. Top of TV is 61".
Tweeter height of mains is 39" and the tweeter height of the center is 67". The front baffle of the center is directed down to the seating area.
In practice this works very well. Dialog localizes well to the screen and there is no hint that the tweeter axis is above the screen. Dialog is natural and intelligible at all listening positions.