We broke and then she told me it was gone... Keep in mind that I paid all the bills

So ? She got to it first, obviously she had a key, and was listed at the bank to get into the box.

The money is gone, and there is nothing really you can do. You allowed her access to the money. Next time remember to keep it more secure.

I agree. Since she apparently had permission to access the box, it is unlikely you have much recourse.

Next time, deposit your money in an account. Safety deposit boxes are for valuable property other than money.