How do you share your feelings with somebody? That's the main question that it comes to.
If you want to tell your girlfriend about your shoe fetish, or any other feelings for that matter, it comes down to communication and how you present it. Relationship is about compromises, its about giving and taking. Almost everyone has some sort of fetish or fantasies or desire. Find out what her fetish or fantasies are, fulfill hers, and in return, she will fulfill yours. As with any delicate subject, take it gently and wait for the right timing.
Be honest. And if it might not be her things, that's ok. Her fantasies might not be yours favorite ether. But as long as you two understand each other, and are willing to help each other out, then its ok.
As far as getting women shoes if your single, that's easy. Just ask for it and offer something in return. Very fell women will turn down an offer for new shoes in return for old pair that she is ready to throw away anyway. Last resort, you can always offer to give her money for her shoes, in another word, buy them.
Hopes this helps. Keep in mine I'm not a relationship expert and this is just my input on the subject.
]