You aren’t kids anymore, and you want to have a grown-up relationship with your sister. Nothing you have tried has helped: pleading with her that you’re not the same person you were when you both lived at home, doing nice things for her – nothing has made a difference. The truth is, sibling rivalry continues to rear its head well into adulthood and even into old age, notes Peter Goldenthal, Ph.D., author of ”Why Can’t We Get Along: Healing Adult Sibling Relationships.” But don't give up; you might be able to put your relationship with your sister on a grown-up track.
Discern the meaning behind your sister’s jealous behaviors. Perhaps she is operating under the influence of childhood labels, such as which sibling is the smart one, which is the ambitious one, which is the most or least likely to succeed, suggests by Jeffrey Kluger, author of “The Sibling Effect: What the Bonds Among Brothers and Sisters Reveal About Us.”
View her expressions of jealousy in light of her childhood labels or issues. If she is jealous of your success because you were the brother expected to succeed and she was the sister who simply had to look good, she may be belittling your accomplishments to feel better about herself.
Prepare a response to her based on her most common criticisms of you. For example, when she sarcastically tells you how lucky you are that you don’t need a full-time job when, in fact, you are living in your parents’ home because your mother requires round-the-clock care and you are single, tell her that you sincerely wish you were sharing care-giving duties, not because of the hard parts, but because then she would also get to have some special moments with your mother while there is still time.
Be clear about behavior that is unacceptable to you. Although you may understand why your sister is jealous of you, that does not give her carte blanche to treat you badly. For example, if she constantly puts you down in front of other people, tell her that you feel humiliated each time she does it and you not willing to be talked to that way anymore.
If your parents still make comments that fan the flames of sibling rivalry, ask them to stop. Telling them, in front of your jealous sister, that such behavior is not respectful to either of you may help your sister feel taken care of by you and might be enough to start your relationship down a new path.