It will take a court action. The legal father will have to be notified and can certainly protest the change. Tons of children have different names than their mother and siblings without being outcasts (thank you very much, I have two step children of my own who have their biological father's name).
You make a petition explaining why such a change would be in the CHILD'S (not yours or your husband's) best interest. You have to either have consent or show you have complied with the notification of the other parent (this has to be legal service) of the petition and the date/time/place of the hearing on the matter. You must file legal proof of this consent/notice prior to the hearing.

