My gosh, I sit here wallowing in my own self-pity over losing a love (moving, not dying, and a love, not a mate) and then I read your story. Sure puts things into perspective I guess.
I ache for what you have gone through. You must be an awesome father...you constantly talked about your girls and making sure their happiness was your main concern. How wonderful for them.
The pain of what your wife did must be nearly unbearable. I cannot even imagine it, so you have my respect just by enduring it. Your plate is so full right now and I hope you can stay as positive as possible for the kids.
I don't know what your plans are as far as divorce or waiting or whatever, but I would suggest seeing an attorney to get something filed as far as legal control of the kids. I don't know what it's called, but I am thinking that if your wife wakes up tomorrow and wants the kids back, she can come and take them in a heartbeat. You would have to surrender them to her and would then be on the "visitation" basis, which would be awful. As you are in the depths of your grief, you need to protect what will happen in the future. And believe me, if she gets the kids, she won't be as nice as you about seeing them, being invited to bday parties and that stuff.
I know money is probably an issue, so go to family and friends and whoever you can to get the help you need right now. You need lots of support.
I am glad that you are here. Maybe we can make your journey a bit smoother. Again, you have my deepest sympathies in what you are going through.