Ouch.

Not sure how useful this is, but if you really evaluate him as that special, do you then expect this to actually impact your marriage negatively? I don't quite have experience with this, but perhaps the first thing you need to do, if you haven't done it already, is actually consider what you expect to happen if you talk to him about it, and maybe actually do so?

(am I misunderstanding your concern here? ie, I'm reading this as "Actually leaving my religion/rejecting those beliefs, if I'm being honest with those I care deeply for, will have serious repercussions in my life, so what do I do?")