Civil rights

You have rights under the Fifth Amendment to the United States Constitution to refuse to give testimony that may have the effect of incriminating YOURSELF -- that is, testimony which tends to prove that YOU committed some criminal offense.

You may also be able to claim -- or your husband may be able to claim -- the benefit of a spousal privilege, which is not based on the Fifth Amendment but also has deep roots in the common law going back hundreds of years.

To get a specific answer and better advice than I've just given, you'd definitely need to acquaint a lawyer with the specific facts of your situation. You want that to be shielded by attorney-client privilege so that you can speak freely. Ideally, you'd have your own counsel -- YOURS, not his, even if you want to be on his side -- who can then coordinate with his counsel AFTER helping you understand the extent to which your rights and your husband's run parallel, and the extent to which, if any, they may possible be at cross purposes. Your husband's counsel may can help you find someone who he's comfortable working with. Unfortunately, you probably would have to come out of pocket to pay for such a lawyer -- the military probably won't pay -- but that's another subject that your husband's counsel may be able to help with. But in particular, if you think YOU might be at risk of being charged for something, either in military or civilian courts, then that's all the more reason for you to have your own lawyer to consult with before you testify.

There are all sorts of consequences to claiming a privilege, and there are only a limited number of lawyers who are competent to evaulate that situation specifically under the UCMJ. When you claim the Fifth to protect yourself in someone else's criminal trial, for example, that may under some circumstances permit the prosecutor to argue that your testimony isn't very trustworthy on any other points (because you have something to hide), even though he can't make that argument about the defendant if HE takes the Fifth. Your taking the Fifth, in other words, might in some circumstances hurt your husband's case more than simply telling the truth -- but it might be bad for YOU.

Don't share any more information on a public website than you already have -- you may WAIVE your privilege(s) by doing that.

Get a lawyer. Talk in person. Good luck!