She has similar opinions about your career goals, friends and pretty much everything else. If you've articulated that you're happy with your life and the people in it and she still won't stay out of your business, then your relationship with your sister could be verging on (if not already) toxic.
A toxic sibling relationship is a relationship that is unbalanced in its power dynamic and may involve sibling abuse and dysfunctional sibling rivalry. Sibling estrangement can be caused by parental favoritism, having immature parents, parental or sibling abuse, and psychopathy.
Remaining in a relationship with a toxic person is potentially harmful to your emotional and physical health and relationships (and may negatively affect your spouse and children, too). The bottom line is that for many people, the only way to heal is to remove yourself from the abusive relationship.
Sibling physical abuse is defined as a sibling deliberately causing violence to another sibling. The abuse can be inflicted with shoving, hitting, slapping, kicking, biting, pinching, scratching, and hair-pulling.
Point out how they're being selfish.
Help your sibling see that by behaving the way they are, they're only thinking of themselves. Don't just tell them they're being selfish, tell them how. In order to make them see the error of their ways, it may help to explain your own or someone else's point of view.
“Cutting off is the extreme answer. Sometimes it's necessary, but in most cases, you can stay connected,” she said. “Like the end of a marriage, sibling estrangement is always sad, even when it brings relief. It's not what anyone hoped for, but sometimes it's the wise and necessary choice.”
The best thing that you can do to try and stop your toxic sibling from hurting you, is to ignore their behavior. When you ignore someone, they will see that they aren't bothering you and they will have less motivation to continue their adverse, disrespectful, and offensive behaviors.
The abuser has the intention of making the victim feel lesser than, creating a sense of low self-esteem or social withdrawal. Examples of sibling emotional abuse include name-calling, belittling, teasing, insulting, threatening, destroying property, relational aggression, intimidation and asserting power or control.
Sibling alienation occurs when one adult sibling wants to push aside another. While sibling alienation can occur at any point, one sibling may be especially tempted to alienate another in order to gain control of care-taking or inheritance outcomes with aging parents.
Be honest about how the toxic trait impacts you
As we mentioned, many people don't realize they have toxic traits. So, telling someone that their actions have hurt your emotional well-being may help them understand they need to change.
Acknowledge your sister's feelings.
Begin your apology by noting that you hurt your sister and that you want to address her hurt feelings. Do not use “if” or “but” when you speak to your sister. Be honest and acknowledge that your sister is upset.
Siblings may be jealous of and harbor resentment toward one another. The main causes of sibling rivalry are lack of social skills, concerns with fairness, individual temperaments, special needs, parenting style, parent's conflict resolution skills and culture.
Gaslighting by a family member is a confusing form of emotional abuse where one person uses manipulation to gain control over another by distorting their own sense of reality.
Adult sibling conflict can arise from disagreements about topics like finances, parenting styles, or major life decisions.
Sibling abuse, just like other forms of abuse, can lead to post-traumatic stress disorder (PTSD).