Do guys always want to cum on my wife's face? What's wrong with this question? I don't have a wife. I AM a wife. Lots of women read this Board and post. A woman runs this Board. Why is the question only addressed to the husbands? After all, we wives are the ones with the faces in question.
I've known women who wanted the man to come on her face. For whatever reason, it's a turn-on. At least one I knew, with a Ph.D., liked how it made her feel "dirty". I would find it degrading, a very basic expression of domination. But I like plenty of things lots of other people would consider degrading.
As to whether guys like to do it, I think at least some of them ARE doing it to feel dominant, and get something out of feeling like they are slightly degrading the woman. I'm sure for some, it's just a general turn-on. I think that would be more likely to come up in gang bang situations.