My psuedo step, nephew CTBB, did this to me when my husband and I hit a rough patch, and let me tell you it cut like a knife. Esp because whenever we had him I did everything for him, and I mean everything. It made me believe the old saying "Blood is thicker than water". Things are 100% better now, but I'll never be as unguarded with him again.

Ah yes, the teen SD. My SD15 and BM sound the same as yours. SD doesn't seem to connect with many except daddy. BM is insecure around me as well. She has thrown out the "you like AA more than me don't you?"

My case may be different because I make it known to her by my actions that I don't buy in to her poor SD act. I don't suck up to her and she knows when I don't like how she is behaving. So she maintains a distance from me because of a build up of these interactions. It is partly me that creates this distance, but I have for good reason. She never showed any sign of opening up to me anyway though. No matter all of the nice things I did for her in the beginning. She doesn't get along with many people since she turned 14, except her daddy and a few friends. Her friends seem to change a lot though. I think they tire of her personality after a while. Daddy still listens to the whining nonsense and she still gets whatever she wants even when she doesn't keep her grades up and lies to her BM about what she does with her friends.

I've let it go. SO and BM can deal with her. There is no longer a reason for me to have any real involvement with her.

I just read an article from StepMom Magazine and found this quote very interesting,

"It doesn't matter how unhealthy the biological parent is; most children will choose their biological parent even when that parent has abandoned them or is deceased. In fact, studies show that teenage girls who have unhealthy mothers will resent even more a stepmother who is healthy and has her act together."

"When a child is faced with the decision to acknowledge a biological parent or step-parent, the birth parent wins every time. This is true even when the parent is irresponsible, neglectful, or abusive. Children have a fierce loyalty to their biological parent. The affirmation and attention they crave stems from a core desire to feel loved, significant, and secure."

It's not you. Don't take it personally. Just hang in there and she'll come around. You've got a great chance of that especially if you had a good relationship with her before. Stay the course and it'll pay off.