It really does become a part of us. Does not mean we aren't healthy or well adjusted, nor does it mean that we never need support again.
I wish I had a dollar for every time I have heard/read, you have gotten what you wanted (to be estranged), why cant you move on/get over it/etc.
In thinking of my experience, no I didn't get what I wanted. I never wanted to be estranged. What I wanted was to have a loving relationship with my mother and her with my kids. I wanted my kids to have a close bond with her.
Estranging was actually her choice, though she would not see it that way. Many years I tried to work through her behavior. She chose not to follow simple boundaries like "do not talk badly about me to my children". Even after hearing what the consequences would be, she lied to my face and did what she wanted to do, which was damage my relationship with my children in order to feed her deranged need to compete with me for my children's affection, among other things.
She, essentially, chose this estrangement Though I am the one who instituted it.
This certainly did not come about all at once. It happened over a series of several years, coupled with a lifetime of toxic behavior towards me.