What is the best way to keep my husband from getting week-end visits with our children?

Are you using an attorney in the divorce?  Then I would advise speaking with him or her before there is a temporary custody determination as to the matter.  What do you mean that he is "not responsible?"  That can mean many different things.  If you mean that he puts the children in danger or does things that are not in their best interest then that is very different from not parenting the way YOU want.  If it is the former then ask about having him deemed an unfit parent - which is VERY difficult to do - in the "best interest of the child" which is the standard. Be aware that judges are not inclined to dent parents visitation.  And fyi there is really no "norm" in this day and age as to visitation. Good luck.