I'll start with the easy part.
You have a partner who is willing to indulge your fetish as part of sex play. No, it is not a turn on for her like it is for you. But she IS enjoying the fact that she is pleasing you.
This is a perfect example of a working healthy sexual relationship. You do things for each other that might not be at the top of your own turn on lists because your partner likes and enjoys it. I'm sure there are some things that you do for her that are not bulls-eyes to you, but you enjoy seeing her enjoy herself. Right?
The second part is a bit harder.
You want to talk with folks that share your likes, in short to communicate with folks who are like minded. As this is an aspect of your sexuality, you seem to be feeling that sharing it with anyone other then your partner is a breach of the relationship. This is also normal. (Both the desire to communicate with people like you, and the guilt)
How to best address that guilt is more complicated and depends on a lot, starting with how your GF feels about outside sexual media and such.
Myriads