Not all women have an spiteful motive. There might be legimate concerns as to why she doesn't want overnight visitation.
Maybe there may be a reason that is a legimate concern for the childs safety that she doesn't want overnight visitation. Not all women are mean and vendictive - some have concerns for the childs safety. Such as a father that is an alcoholic and puts the child in harms why by putting that child in a car after he has been drinking. Or maybe that father on numerous occasions has passed and left something on the stove cooking and the mother doesn't want the house to burn down one day with her child in it because the father passes out. Before you jump to conclusion's and say fight her, fight her stop and think maybe there is a reason and maybe that reason is for the safety of the child.
I am not saying that this is the situtation in this case but I just wanted to inform people that there are 2 sides to every story. People sure jump on board to give an opinion without knowing the facts.