Contempt of court charges

My husband and I recently got married. And his ex wife isnt to pleased about it. They have two girls and a custody aggreement already in order. Their papers state the girls reside with the mother through the school year and the father gets visitation every weekend except the first weekend of the month. the girls reside with the father during the summer months and visitation for the mother has to be mutual concent. For the last three years she has not seen the girls at all in the summer, except last summer she had a family reunion on the forth of July weekend and my husband let the girls go. This summer she has insisted she still gets them every first weekend of the month. When we made plans already. We kept the girls, and my husband was just served with contempt of a court order. Do we need to take an attorney with us for our first court date? My husband was going to let her see the girls next weekend, but now im not sure he should. I know if she decides to keep the girls the rest of the summer from us theres nothing we can do.
Any help would be appreciated
Thanks

If the order does not specify that the children are to visit with their mother the first weekend of every month, your husband should not be held in contempt- he can represent himself at the hearing.
If the two of you don’t have any plans with the children next weekend, I see no reason to allow them to see their mother.