Step-parenting a teen often feels like walking a circus tightrope through sniper fire without the applause at the end. Parenting experts Gina Kemp, M.A., Jeanne Segal, Ph.D., and Lawrence Robinson for Helpguide.org observe that teens often struggle more with blending families than younger children do which can exacerbate typical self-centered behavior into something intolerable. However, if you grit your teeth and bear it, you aren't doing your step-daughter any favors. After all, you'd fire an employee who treated you the way she's treating you. Work with your spouse to develop a plan that provides you with the respect you deserve and teaches her the skills she needs.
Understand that typically developing teens frequently appear self-centered. The development of an identity separate from the family requires a great deal of inward focus. If your step-daughter is like most teens, she may appear preoccupied with herself as she compares each action, thought and desire with those of her peers or an idealized adult. This compare and contrast game helps her grow into the woman she wants to become, but it also can be frustrating when she seems unwilling to consider the needs of those around her. Use her desire to grow as a tool to help her see how her behavior impacts others by having her imagine what a teacher, peer or coworker would think of her behavior. Focusing on teaching her life-skills for working with difficult people outside of the family can diffuse the emotional tension of blending your families while reducing some of her self-centered tendencies.
Work with your spouse to develop house rules. It often takes many years for teens to love and trust a new parent enough to accept her guidance. This does not, however, negate your need for respect. Your spouse can help you figure out a set of expectations that allow your step-daughter to participate in family life in a way that makes sense to her based on past rules while helping her learn to accept and respect your needs. For example, if she's used to eating whenever she's hungry and you're trying to establish family dinners, work with your spouse to compromise so that she eats with you on certain nights or sits with the family even if she's already eaten. Then talk to her about her need for independence and your need for family time so she understands she isn't being punished.
Focus on developing empathy. While a certain amount of inward focus enables your teen to emphasize her strengths and improve her weaknesses, parenting expert Michele Borba, Ed.D suggests that self-centered, disrespectful teens may fail to develop the skills they need to develop healthy adult relationships. As a step-parent, you play the valuable role of a new person that she has to learn to get along with. Helping her understand how you feel when she behaves selfishly illustrates how her behavior impacts all of those around her. While she may be extra difficult in an attempt to push you out of her life, your persistence can help her learn to love not only you, but a difficult boss or in-law in her future. Tell her how her behavior makes you feel and ask her to imagine how she would feel if a friend treated her the way she treats you. She may not answer you, but she will have heard you and hopefully she'll internalize some of what you say.
Defend your rights. As a member of the family you have certain rights and it's in your step-daughter's best interest -- not to mention your own -- to insist on them. Among other things, you have the right to be treated respectfully and kindly, the right to finish a meal, the right to have your things left alone and the right to privacy. If she pushes, remind her that her future roommates will have the same rights and she might not like them either. Work with your spouse to make these expectations clear along with the consequences for violating them. Acknowledge that growing up is difficult and that sometimes she'll need to act selfishly, but that her needs do not supersede yours. Conversely, confirm that she has the same rights and you will respect them as long as she respects yours. Only you know where your bottom line is. Clarify this with your spouse and then work together to establish a new set of household rules that meet all of your needs so that you feel less abused and your step-daughter learns some valuable relationship skills. It may mean that she does the dishes after an hour of texting, but if she does them without a fight you will have gained an active participant in your family routine.