Hi there Tiger,
Here is my contribution to your curiosity... I used to hate it now I love it.
I don't quite remember any particular eureka moment, but it was probably during my sexual liberation period after my divorce when my horizons expanded and my mind (and other parts) opened up to many new experiences.
When I try to go back in my head to the time I did NOT like to be kissed after oral sex, I think it was the intensity of the smell and all the juices after cumming that drove me away. Maybe there was also the thought of it being 'dirty', but that didn't play a big part, I think it was more physical than psychological.
A practical suggestion for you is to keep a small towel by the bed and wipe your face after the oral sex and see if that makes any difference for her. Even without kissing she may feel more comfortable being closer face to face that way...
By the way, I can tell you many men don't like to be kissed after you give them head either... I've been with very few men who actually liked the taste of their own cum.
My 2 pence/cents,
Ali