wantobehealthy, I feel for you but I have learned plenty from having to be in litigation. I think I understand the story is that you are divorced or in the process? or separated? and the state is pressing charges for assault.
I might be wrong...but if custody is not already decided or even if it is, remember anything you say can be used in a future custody trial. So, if you lie for him or minimize this or make him out to be a great drunk...it will come back to bite you later should he file for custody or a modification.
The best advice I give for anyone having to testify is LISTEN carefully to the question. Do not give an answer to a question no one asked. Lawyers do NOT ask questions they don't know the answer to. (unless they are stupid or sure they have intimidated you) And, yes, no eye rolling, no sighing etc., try to maintain composure if they try to put you on the defensive. Never feel the need to guess at anything. (a rape victim I know tried to guess at the time she was raped thinking that was helpful, it totally messed up her defense because she was supposedly under the influence of a date rape drug. At trial, she logically estimated the time....was the wrong thing to say) "I don't know" is an answer. Don't feel you need to help by guessing. If his lawyer tries to cut you off its because what you are saying isn't helping his client. If the Prosecutor hasn't talked to you call and ask them if they can give you a summary of what kind of questions will be asked. Good lawyers prepare their clients. He'll be prepared.