Having grown up as a JW from infancy, I would suggest you need to break the chain of thought that Jehovah is this personal god who looks down on your kids and watches everything they do. The indoctrination that they need to be worried/guilty about anything they do is something that runs deep for JW kids. If Jehovah is not real to them, they won't be pressured into thinking that questioning is wrong. A parent's example is a powerful thing. A child will take notice of how their parent acts, and be persuaded to think that they too should do things jehovah's way. If their parent sees jehovah as a real person, the child will be likely to follow suit.
It will be difficult to try and show your children that your other half can be wrong about something, while at the same time trying to maintain your children's respect for his opinion. I would say try and teach them a bit about all religion, and get them to try and understand how different religions started/developed etc. Try and include the JWs in your discussions, so they can see religion in a broader spectrum.