We don't have $10,000 in a bank account...(think I saw that as a threshold for something)
The $10K is the magic amount for FBAR (now FinCen) reporting; this is separate from a US tax return. The requirement kicks in when the aggregate value of all foreign financial accounts that a US citizen either "owns" or has a signature authority is $10K or over. It's not just $10K in a single account, and it's based on the maximum value of each account at any point during the year.
For example, say you have $5K in one account on June 1. You open another account and transfer $4K to the new account, and leave the first account untouched. You start making deposits, and in September (or whenever) the second account has $5001. Even though the first account has only $1K, the maximum value was $5K. So for FBAR, it's $5K + $5001 = $10001 and you have to file. Accounts that you, the UKC have in your name only, and that your husband doesn't have signature authority over, don't count.
FBAR can get complicated, as financial accounts are more than just bank accounts. Your husband needs to be aware of the reporting requirements. FBAR is only filed on-line, and must be done by June 30 (unless they've changed the date for the 2015 filing - I haven't looked).