Joint custody passport

Hallo friends, My Mutual consent divorce is stuck up in a point where the husband is insisting on joint custody of the child's passport in a joint locker or to be deposited in the court. He has a fear that i may run away with the child having visa of 3 countries. I assured him that I am ready to give an undertaking in the consent terms drawn. But he is adamant on having a in joint custody. He has also agreed to give an undertaking that he will never disallow the child in taking abroad for vacation and further studies. Please advice whether this arrangement is suitable. It is very urgent I am about to sign a MOU