My husband had an affair with a relative. She works for Wells Fargo as a CPA. She assisted him in opening a Wells Fargo credit card account online, and had her home address put in as the mailing address, so I wouldn't find the new card in our mailbox. She gave him the card, after receiving it. Then through the computer system at her bank, switched him to online billing going to his email address at his office. Of course this bill was being paid through our joint checking account. Does this amount to credit card fraud,or other criminal behavior on her part?
You're still married and your husband incurred the charges. The debt is community debt. You might consider closing the joint checking account, and opening one at another bank solely in your name. Then you can consider the future of your marriage.
Also, this is what is called a "breach of fiduciary duty." You might not be held responsible for it.