Though my experience w/r/t discovering the Christian aspects wasn't so wrenching, I also didn't really reread the books after I found it out, and that was a dozen years ago. Speaking personally, I think I've come to appreciate and understand how much I still love the books all the more for having done this reread, and I've come to a better grasp of how the Christianity--which Lewis obviously put and saw there, but which isn't necessarily obvious if you're not looking for it--fits in with the other elements of the books.