How can I get my girlfriend to accept this fact about me?

I don't have a girlfriend yet but when I get one I need her to accept this about me. I have a belly button fetish, I like an innie belly button on a girl more than I like her breasts or butt. I want to tickle a girls belly button by sticking my finger in it and wiggling it around, kissing it, sticking my tongue in it, and blow raspberries on the belly button. When I tickle her I want to grab her sides and then stick finger in my belly button. I want to tickle her during cuddling, at the beach, or when we're laying down I want to reach over, stick my finger in her belly button, and blow raspberries on it. I really want my girlfriend to be accepting of my navel fetish, and for us to have tickle fights that will involve the belly button being tickled. How can I get my girlfriend to accept this about me?