What sandi said... you might be correct in 'hoping this is part of some crisis', but even if it is part of the crisis, it could still happen.
As other advised on here, I would find yourself the best dang L you can find dealing with child custody. I'm not 100%, but I don't think one spouse can just up and leave, and take the kids in the process without some formal agreement between the two.
I'm not a lawyer though, so I'd hightail it down there ASAP.
