Actually she doesn’t hate you she hates what you represent, revealed the Huffinton Post.
She can’t accept the failure of her marriage, the breakup of her family, the woman her ex-husband became a better man for and also fear that she might have ruined her child’s life by not being able to make the marriage work.
She perceives you as overstepping boundaries. She resents your participation in events she believes are reserved for “mom” and those that may not be reserved for mom but that are “firsts.”
These might include taking your stepdaughter to buy her first bra or getting her first haircut, participating in any sort of cosmetic experience, talking to her about the birds and the bees, painting her nails or coloring or cutting her hair the way you like it or similar to yours.
She has unresolved grief about her divorce. For a long time, she could just ignore the painful feelings that accompany divorce. She didn’t really have to face it. She may even be remarried but never actually grieved the loss of her marriage and family. Enter stepmom, and suddenly it’s real and it’s in her face.
You act as a mirror for her. When she looks at your strengths, all she sees are her weaknesses. She perceives you as doing all the parenting while dad is “let off the hook.”
She doesn’t know you. When mom sends her kids off to be with their dad, and this woman she doesn’t even know will have full access to them, she may feel like she’s being a bad parent.
She sees her ex-husband being a different man with you. It can be painful to see the man you think treated you so poorly treating another woman like a princess.