I've been in this exact situation before, Anika, and it's brutal. I felt like every time he looked at me while I was reading, or tinkering with something, or if my friends were over and we started talking he would treat me like a child. Like he was better than me, and like I was an idiot for what I believed. It hurt, deep.
The way I solved it was I eventually broke, and just yelled at him every time he did it. I would go ballistic and tell him exactly how I felt and how it hurt whenever he brushed it off like it was nothing. How I felt like I suddenly became the stupidest child in the world. How I felt betrayed. How I felt belittled, and judged, and that would make me feel worse about myself. In hindsight, probably shouldn't have started yelling, but it got my point across.
My advice would be to sit him down, tell him exactly how it makes you feel when he responds that way, and ask him not to. Ask him to say stuff like "Oh, cool." or "oh, okay" when he asks questions about what you're reading. Or to try and be respectful. He needs to realize that it's his girlfriend he's talking to, not some random person on the street (although that's still inappropriate it's more socially acceptable). Try and figure out some basic stuff that he could stay instead. Be honest, and be firm about your feelings. Make it more about your feelings than beliefs.
Most of all, I think it is possible, but will be hard. I hope one day you two get to a point where you can talk about your beliefs and not be at each others throats, or hurting each other by accident or something. I find it scary talking about what I believe in now because of how my ex treated me for so long... but the funniest part is that after we broke up, he started looking into it and is now practicing the very thing he'd mocked for so long... and it annoys the hell out of me!

But truly, I think it is possible but it's going to take some work on both sides (his more than yours based on what you're saying).
Another important thing is to find other people you CAN talk about this stuff with. Talking about spirituality is one of the best ways to get insight and knowledge into it, and it brings a sense of support and peace. I've never found anyone with the same beliefs, but I can talk about it with most of my friends, which is really nice. If you have other people who you can talk to, it'll help get the need to talk out a bit, and although it would be nice to talk to your bf about this, it would not feel like you're bursting to do it as much.
I think it's great that you're exploring your spiritual side btw Anika, and I want to tell you it'll be really rewarding. I always get a bit brighter as I study spiritual stuff, and I'm piecing together my own beliefs in a way to find who I am. It's really healing and enables you to reconstruct yourself to who you want to be, especially if you've gone through some tough times. Plus, I love the hunt for one's personal truth!
Good luck on your journey, and good luck with your boyfriend. I hope things work out for the best.
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"You can't hop a jet plain like you can a freight train" - Gordon Lightfoot
"It starts with light, and ends with light, and in between there is darkness" -I forget
"Got to kick at the darkness 'til it bleeds daylight" -BNL