This is a super interesting thread, reading how everyone expresses (or doesn't) their collection. I'm a bit of an inbetween myself, because I don't outwardly talk about it or anything but there is a huge bookshelf in my room full of ponies so they're hard to miss if you go in there. I started collecting in high school and back then it was definitely something I hid. My closest friends knew of course, some even collected with me for a bit.
Now that I'm older I certainly don't care what people think anymore, haha. Most new friends and people who see my collection think it's the coolest thing. One guy friend told me he even respects me more for it
And with a boyfriend it's tough, but I was very open with my boyfriend about it. He doesn't like them personally (like he wouldn't collect or anything), but he's fine with my collection because it makes me happy and that makes him happy. He's also kind enough to watch MLP:FiM with me! Applejack and Fluttershy are his favorites, hee hee.