Divorce possible. How can I prevent her from moving the kids?

[LdiJ]

Is there anything we could sign that would prevent her from keeping the children in FL, if we later end up divorcing?
That by the way is my greatest fear. The one that makes me even more reluctant to move in the first place.
I believe that it may be too late, once I agree to move. Then FL, rather than CA, would be our home state.
Maybe I could draw a contract that specifically addresses that.
Namely, that in case of divorce, the children would return to CA.
Thus making the move to FL, a "trial period", not permanent.
Would a written agreement like this, if signed and agreed upon by both parties in CA, be enforceable in the State of FL?

Thank you.

I don't know that anything that you could sign now, that would required the children to move back to CA in the event of a divorce, would ever be enforceable.