Mother is very important for child, since they have that special bond since the beggining. It is very clear that child needs both parents but if he has to choose, he will choose mother in 99% of the cases. If father gets another wife, (he will try to make his wife happy and not pay so much attention to his child) the child will be treated differently by father, but if the mother gets another husband, the child will be treated the same by his mother "because they will always have that special bond no matter what happen