A joint account allows you both access. This means he cannot stop you accessing it and you cannot stop him. The only way is to stipulate to the bank/building siciety involved that cheques must be signed by both parties or limited sum withdrawals by both of you.However this must be set down at the start because most couples use this method to pay the mortgage, bills etc..
It does mean though that if you go to your bank they should give you another card and pin. You can simply say you lost it.
I suspect it will involve a personal visit to the bank and some I.D.
I hope this helps, please reply if there are further points.