Twins are often each other’s most intimate confidant. They share secrets, tricks, failures, and successes—no holds barred. They reveal thoughts and behaviors to their sibling without feeling judged or ridiculed. They have a sense of acceptance and understanding, no matter what.
Occasionally, however, this stipulation is not honored. I have worked with a few twins who have deliberately chosen to keep significant secrets from their sibling to avoid upsetting the perceived balance of their connection. This hidden agenda emerges when one twin becomes romantically involved without telling the other. The coupled sibling is determined to prevent his twin from finding out about this attachment for fear of creating uncomfortable competitive feelings.
Unfortunately, what may have begun as a well-intentioned choice becomes a huge point of contention. The one who kept the secret says he did so out of respect for his sibling; however, the one who finds out about his twin’s new relationship from another source feels enraged and betrayed. He does not appreciate being kept out of the loop, nor does he accept the rationale that his twin was trying to protect him.
This same dynamic can turn dangerous when it causes one or both twins to develop an eating disorder. If one twin desires to be thinner than her sister, her competitive feelings might develop into a serious psychological condition that requires medical and psychiatric intervention. Alternatively, while one twin may strive to be thin, her sister may decide to gain weight to create an opposing dynamic. Both situations reflect the pair’s unresolved conflicts and undifferentiated selves. Identical twin women seem to suffer more from these issues because of their close attachment.