ex running up debts?

is there any way to prevent my ex taking on new debt during the period between separation and settlement?

For obvious reasons, if the parties are getting divorced, there are severely practical reasons for wanting to close a joint account down and agree how the balance standing to the credit of the account is to be divided ( or how the balance on an overdraft / credit card is to be allocated ).
There are risks for both parties that the other will drain the account or, worse still, run up an overdraft or go on a spending spree for which the other could be wholly or partly responsible.
If the parties cannot agree between themselves to close the account then it will be necessary to contact the bank or credit card provider. Some of them have procedures to deal with such requests and the answer may be to freeze the account or close it to future purchases. Some banks will require the signature of both parties to close an account.
In any event, freezing an account can have other practical implications. You won’t want your wages or other credits paid into a frozen account. You may need to make other arrangements for bills paid by direct debit or standing order. It’s important to make sure that neither of you is left without money.

LMM