As usual, Molly gave you some good advice. I would like to add--don't think you won't get custody of your kids. It will take work but times have changed. Back in the 50s and 60s, judges would only give kids to the father in what they thought were extreme cases. Most judges operated on the--at times, false principle--that kids always need to be with their mother. Start documenting all her actions. Research your local laws and see if you can tape record her without her consent. It's crucial to get documentation, especially if your wife behaves differently when she is away from the family. Go to a good divorce lawyer for a consultation. Even if the consultation isn't free, it still is money well-spent. My brother was in a relationship with a psycho woman but managed to get away and get custody of the kids.
As a kid who grew up with a verbally, emotionally and sometimes physically abusive mother and a father who allowed her to continue to behave that way, I can't stress enough that you and the kids need to get out.