I take it that you and your wife are staying together , even thou she is staying a witness and you are just stopping meetings?
My hub and I left at same time, but had some explaining to do the children, because we just stopped all of a sudden.
The oldest son understood and was tickeled pink we were quiting, he saw the crap with JW before we did.
The younger two were more delicate. They didnt care if we didnt go to meetings anymore , they hated them. But we just told them we still love Jehovah and Jesus, and that Jehovah and Jesus, love us as a family. My youngest son had alot of armeggedon nightmares and was worried that we didnt love Jehovah anymore. We told him we loved him very much and that he was doing nothing wrong, by not going to meetings. We told him Jesus would protect us if armeggedon came, he is a very loving person. Now alot of this we were not sure of ,,,,,,,, we didnt know what to believe ourselves. At the time I still pretty much believed in God. So I stilled used the name Jehovah for my son's benefit. I didnt tell him too much info,,,,,,, basically we kept it on the level that Jesus will take care of us, don't worry. It took a few months but he got over his fear and now is a happy little boy. He still prays , and says Jehovah most of the time. I don't stop him from praying or talking about Jehovah, I know in time he will come up with his own answers. I just try to tell him what I think will happen when we die, he is very concerned with this....... I tell him we will be together, in heaven or on earth , somewhere, I want to believe this, and he really needs to believe this right now, telling him any different would hurt him , and who am I to say, I honestly don't know what to believe. But I do tell him it could be this or that way, but we will just have to wait and see.
I hope your wife will respect your wishes as to letting your daughter know how you feel , even if it is not JW teachings anymore. Tell your daughter you love Jehovah and Jesus and you just need some time to rest. Give her months to adjust to this and she will. As long as your wife and you dont play tug of war so to speak with your daughter........ I am sure you wont, you sound like a loving father,,,, she will see both sides and continue to love and respect you as her father. She will see that the love her father gives her is more important than being in a religion. Like I said before with kids this age , things change so fast and I for one was surprized at how deep my children thought things out. You can't hide true feelings from them if you are close ,they will sense it,,,,,,, but you can protect them by not telling too much too soon. When they are ready to know something , I am sure you know, they will darn sure ask, and ask, and ask.
Good luck, and keep us posted on how this is going.