No and it never was. How can gagging be considered sexy? Nature gave women a vagina to satisfy every inch of your manhood - you don't need to be shoving it down a woman's throat! Your wife has sense - more power to her.
I agree with that it is probably not something that necessarily has a function in a healthy relationship for the very same reason that it can be so great in porn.
Receiving a deep throat fuck puts a woman in a very submissive position; the man grabs her by the hair and uses his leverage to control her motions which gives him the ability to use her mouth and throat more or less as he pleases. Or, as in my favorite variety, with the woman on her back with her head bent backwards, allowing the man free use of her throat. I would say that the whole point of the exercise is more to dominate and create discomfort for the woman than to satisfy the manhood.
So in pornography, as in sexual relationships of a commercial nature, it definitely has its place. I am sure that many women who do not do it themselves still enjoy watching other women being used that way.