It's natural, we know the very best and the very worst of one another, and it makes us cautious with one another. BUT also, it is an unbalanced relationship that seems tight but is unfair....relationship, where the parent expects perfect obedience from a child, and yet the child expects a Wizard or Hero Of the parent. I have not come up with the exact metaphor for the two extreme expectations, but when those expectations are out of balance, chances are the parent experienced unrealistic expectations from self, or parents, or their community.
It is okay. Our job is to live and love without intentionally hurting others. Try to enjoy or respect both moms, even if one is harder/easier to love.
Okay that my unasked for response, but I hope it soothes any guilt you MIGHT feel.