First of all I just want to say that I'm sorry you're having to go through this. It is sad that religion does this to families. I am also sorry to have to disagree with a lot (not all) of the comments on here.
To me, honesty is always the best route, whether you're a religious person or not. For your kids sake, I would tell your wife that you love her and you want to remain a family, and that you have a right to have doubts and do your own research without the society's permission. I would definitely see a lawyer to find out what your options are. If your wife mentions divorce, then tell her that you don't want to and the elders have no right trying to break your marriage up, which is against bible principles anyways. If she absolutely insists on separating, then that is her choice, and I would resist it however possible - everyone including your kids and other witnesses will see that. Even if you separate, that doesn't mean you have to agree to a divorce. That will show her that you truly love her and want to stay together. Do everything in your power to remain a good father, and openly discuss doubts with your children. They should be taught to question authority anyways, and not blindly follow what someone tells them without finding out if it's actually true or healthy for them! Don't you want them to grow up being able to think for themselves? being able to do what will make them happy in life, not just what the JW org. will restrict them to?
Here's my story, which is living proof of this. I'll try to be brief as possible.
My son Jordan is 14 - his father Ray is still a JW, but now disfellowshipped - but he still firmly believes in their teachings, we just don't talk about religion at all, so we remain on good terms. We married before our son was born, then divorced 7 months later while I was pregnant (ex's choice - he even cheated with a prostitute to be considered 'scripturally free'; how warped is that?). We were both dfd during that time for premarital sex, which of course is rediculous because we did end up marrying. Anyways, I was reinstated when our son was 5 months old; I can't remember if Ray was ever reinstated or if he's been dfd all of this time. Jordan has lived with me since then, but his dad is a good father and has frequent and regular visitation.
After about 7 loooong years of my trying to be a good JW, I started having issues with JW teachings, and realizing that I just wasn't happy in the organization. I started dating non-jws, and eventually was dfd again. But this time, I was NOT repentant, because I realized that the elders didn't care one iota for me or my son's happiness, just if we were in the cult or not. Weird thing happened - my ex became attracted to me again, and we dated again bc I had always wondered if it would work out for us. Ray asked me to marry him a second time, and I accepted. It was nice for awhile, and he knew that I was unsure about whether I wanted to get reinstated again or not. Then we both came to the conclusion that we just weren't good together as husband and wife, and that our goals in life are completely different. I have to admit, I did cheat on him, which is the one thing I truly regret, :( but I know that even if I hadn't, we were going to divorce again anyways. So, we divorced and we've been separate for about 5 or 6 years (I lose track...)
Ray and I have good communication, plus we respect each other's beliefs so we don't even discuss religion so we don't argue about it. I talk with Jordan all the time about just about everything - he's a smart kid, and very open and honest. He knows what his dad believes, but he also sees that I'm happier since leaving the JW religion, and that I'm now going to college, and doing something with my life and we have quite a few friends. I've taken him to a couple different churches in the past few years, to give him an idea of what religious people outside of the society are like, plus he knows that if his dad does want to take him to a meeting, he can if he wants to, but doesn't have to. I really don't think Jordan ever would go to one again, because he's learning to make up his own mind, and he's sees the hypocrasy and unhealthy way of life that devout JWs lead. He also sees that his dad is a wonderful father whether he is an active JW or not, and I can thank Ray for that anyways. Jordan's seen how my family and past JW 'friends' have completely cut us off because I made it known that I was not coming back 'in the truth'. I think that has helped him to learn to discern who his true friends and family really are. My younger sister, and my cousin Teresa are the two family members who are not JWs anymore either, and we are still close. It took time, but I've made new friends, who are TRUE friends.
My younger sister never got disfellowshipped, but did the 'fade' thing. So, although she's living a non-JW lifestyle, family and many JWs still talk to her. Personally, I can't live that way. I'm glad that I was dfd because now I'm free, and I don't have to pretend and my position is clear. My son is not any worse off - he is better off!
So those are my thoughts about it, take it or leave it. If you and your wife ever do separate, I would make it clear to her that you wouldn't want to keep your children from their mother, that they need her. Let her see that you can work it out, visitation, etc. and let it rest on her head if she uses the children to try to manipulate you. Tell your kids that you love them, and you want the best for them and that they are the most important things in both of your lives.
If you believe in God, then pray about it. I no longer pray because I'm now agnostic, but I know that the majority of people do have faith in a god out there who listens to prayers.
Best of luck and happiness to your entire family! :)