The only means of legally stopping this mess is to petition the court to dissolve the LLC on grounds that the partners can no longer operate the business effectively. Simultaneously, you could ask the court for a restraining order on the business accounts, so that only bills to vendors can be paid, and no additional funds can be appropriated.
Alternatively, you could offer to buy out your partner, or sell him/her your interest. But, if the partner is stealing from the business, you must either terminate the operations or simply allow the misappropriation
to continue, because you don't have much choice -- given that you do not want to operate the business yourself.
That's really what it boils down to. If you permit your partner to continue operating the business, and for example, he/she does not remit sale tax to the state, you could find yourself stuck with a huge tax bill, because your partner won't be able to reimburse the business for the unremitted sales taxes.
So, you will have to make a choice. Get involved in the business on a daily basis, so that you can stop the bleeding; buy out your partner; or sue to dissolve the business, if your partner won't voluntarily agree to close the doors.
Please let me know if I can be of further assistance.