Wanttobe, I'm a former foster parent and have dealt with a lot of CPS workers.
Some are really good, and some are complete idiots. I learned to be a strong advocate with the idiot ones --- you have to. You do it politely but very firmly. The workers are NOT always right and they are NOT always properly trained in procedure. If you ever get in a situation like that again, tell them you are afraid of your husband and will not be alone with him under any circumstances. That was terrible that the worker a) left you in a room alone with your husband while she interviewed your girls and b) interviewed a child who knew her parents could hear her comments.
Remember, this may come back as 'unsubstantiated' this time around, but someday it won't. Your XH will eventually drop his guard and f*** up.