I also wanted to reiterate that there's nothing cowardly about writing an email vs. talking to them in person.... It isn't the means of communication that matters, what matters is you're needs are being heard and taken into consideration.
The BDSM element probably adds a layer of complication onto the situation that's a bit tougher to muddle through than some of the rest of it, I would say... Especially since your partners are into it but you're not at all.
These I'm asking more as rhetorical questions (though if you feel comfortable, feel free to share)... What are your quads guidelines about sex? Is having sex as a group a necessity or can you break off into twosomes/threesomes as you see fit? If you're going to have sex as a group, can certain activities be off limits so no one feels left out? In your shoes, I'd be asking myself and my partners these questions to figure out what will work to make sure everyone's needs are met.
And you're right, Lemondrop... Polyamory isn't easy, it takes a lot of communication, negoitation skills and patience.... I personally feel that it's a rewarding endevour though.