@merit.ahama Perhaps you have kept the separation of parents as the gland of your mind, but there must have been a big reason behind that divorce, which you cannot understand because you are young, maybe you will understand till the age of the father. Accept the new mother. It is also true that no one can take the place of the original mother.
True, no other can replace the first mother and she didn't replace any... She just respected her father's decision and loved her new family.