The Marvster... excellent observation. This is what I've seen as well. JWs swerve off the course of discussion because they cannot refute things. Either that or they clam up. My Dad used to just stop talking because he couldn't come up with anything. This was accompanied by the stunned deer-in-the-headlights look.
goingthruthemotions... have you ever thought of buying Bart Ehrman's book 'Misquoting Jesus' and just leave it out where your wife can have a look at it on her own? There's some good info. about the gospels contradicting each other in that book.