Barbara Klein, Ed.D.

https://www.newyorker.com/magazine/2000/12/04/we-two-made-one

https://www.psychologytoday.com/us/blog/twin-dilemmas/202209/how-you-can-get-along-your-twin

https://www.psychologytoday.com/us/blog/twin-dilemmas/202208/how-stay-close-your-twin

Can Hallmark Cards Reconnect Twins?
    After reading my books and articles on twin development, twins have reached out to me asking for help understanding their anger, fear, or just plain unhappiness with their twin. Certainly, it is not uncommon for me to hear that finding a mental health professional to help a twin get along with their sister or brother has been difficult. Sometimes a therapist suggests that sending their twin a beautiful Hallmark Card might be the answer to their issues. My twin readers are more realistic and more “in pain.” They are thirsty to heal their confusion, loneliness, anger and despair related to being a twin in a non-twin world. The idea that twin issues can be understood easily is ridiculous. Twin relationships are nuanced and complicated and frequently very entangled.

Identity Confusion Is “Normal” for Twins
    I ask myself why finding support with twin disappointment is so hard to come by in our psychologically-minded world that is overflowing with self-help advice. And I think that the  underlying reason is that mental health professionals don’t understand the depth of the twin attachment, which can create a highly conflicted twin relationship and identity confusion. Naturally and inevitably, so much physical and emotional closeness causes “over-identification”—enmeshment or entanglement between the twin pair. “Who is who” identity confusion is a common problem that twins need to disentangle and deal with together and alone.

Problems with Over-identification for Twins
    In general, problems that twins have with each other based on their over-identification seem to fall into the following categories:
    1.  A love/hate roller-coaster relationship that is based on longings and expectations for closeness. In most of these situations, disappointment, fighting, and then making up have become a commonplace but dysfunctional way of interacting. For example, one moment a toy is lost that belongs to your twin and the world comes to an end. Just as quickly, Mom finds the toy, and joy and happiness are seen in the resultant twin play.
    2.  A seriously unbalanced relationship where one member of the pair is super-special and the other feels like she or he are invisible or “should be” invisible. Parental favoritism fuels this unfortunate aspect of the twin relationship.
    3.  Continual fighting over “who knows best” and “who needs to be the follower.” (This is much more serious than a dominance/non-dominant issue and a seemingly impossible problem to solve.)
    4.  Twins who cannot get along and make it impossible for their parents, children or cousins to see one another at family events. Family strife over these types of problems are extremely painful and hard to resolve, especially around holidays and family celebrations.
    5.  Anger and resentment that one twin is more successful than the other. Even with good-enough parenting, this type of competitive behavior is very difficult to diffuse for both of the twins. The successful twin may feel guilty and the “less than” twin can become angry or self-loathing.
    6.  Separation fears and anxiety when new partners are introduced into the lives of the twins. For example, the anticipation of sharing your twin’s joy in marriage is always very difficult and confusing for the twin who is the bridesmaid, not the bride.
    7.  When twins want the same thing, from dresses to grades and houses and even romantic partners, deep anger and resentment can arise and lead to fighting and estrangement.
    8.  The world does not understand twin disappointments and dismisses them as an over-reaction. Twins get trapped in the middle, longing for support, but they get no compassion for their twin problems. Being a twin is a “perfect and ideal” relationship for uninformed non-twins. Really, being a twin is a very difficult challenge.

Twins Inevitably Feel Misunderstood
    Loneliness and feeling misunderstood is extremely common in twins, whether or not they are estranged or have a workable relationship. Here are some ways to counteract or diminish your loneliness.
    1.  Psychotherapy that takes into account your twin problems as serious and worthy of attention in the therapy session. Therapists who dismiss the twin problem as “secondary” cannot be helpful.
    2.  Reading and understanding what it means to be a twin in a non-twin world.
    3.  Finding twin friends who want to explore your twin reactions with you.
    4.  Sharing what you know about twinship with your family and asking them to help you overcome the roadblocks that you and your twin share.

    In conclusion, when you find solace in your own life, problems with your twin relationship become less intense and much easier to put into perspective. Loneliness and searching for twin replacements is a predictable way to develop self-confidence for twins. However, when too much closeness is expected of twin replacements, then unhappiness, disappointment and loneliness reappear.

https://www.sfgate.com/local/article/Marian-and-Vivian-Brown-famous-San-Francisco-twins-16330809.php

Being a twin is challenging for the many reasons that I have written about in previous articles and books. And if you are reading this article you probably have your own list of frustrations with your sister or brother. Surprisingly, in spite of understandable frustration and competition, many twins manage to get along with each other. Some twins get along out of necessity, as they feel they need each other to survive—they are overly dependent. Working together on a career goal or a project also promotes positive feelings between twins. Or oftentimes twins respect each other for their life choices and accomplishments. What can we learn from twins who share their lives openly and without overwhelming anger and resentment?

Basic Necessities of Getting Along
Valuing individuality and differences between each other
    First and foremost, twins who can get along are concerned with their individuality and value being different from their twin. While twins who get along may enjoy and respect their twin's perspective, making their own decisions is totally within their emotional and cognitive capacity. In other words, what their co-twin has to say is valuable but not the answer to the decision that needs to be made. For example, my sister may be interested in my point of view on what to wear to a meeting where she is a presenter. But she does not need my advice to make a decision and usually does make up her own mind. And obviously my sister can write her own speech. In contrast, my anxiety about giving a presentation is very high, so my advice on such would not be valuable. We have different strengths and challenges.
    Twins who can communicate with each other have for the most part processed, understood, and put behind the jealousy of childhood and adolescence. “We get along” twins don't need to agree on what went wrong and what went right in their family life. Respect for one another's thoughts and feelings is what is important. As adults they have worked on their communication pathways. Using the self-reflection of psychotherapy, education on being a twin, and establishing time together that is structured and productive, they find ways to share and dialog. Fighting is not a weapon that is used to win a dispute. Rather, when problems arise twins who have a healthy attachment work together to find a resolution.

Ability to see life choices differently
    A healthy twin attachment is not based on the obsession to always be close and in agreement. Distance and independence are seen as important parts of the twin relationship. As well, separate friends and separate interests are extremely valuable. Family events that do not include favoritism contribute to a strong twin bond in adulthood.
 
Personal boundaries between the pair are based on respect
    While this idea may seem simple to abide by, in my experiences with twins it is very difficult to achieve. Because of the intensity of feelings between twins, respecting one another can truly take time and patience. For example, it took my twin many years to accept that every time she called me I could not and would not pick up the phone. In other ways I was more open. For example, we could share clothes, thoughts, feelings and definitely opinions, but I could not make myself available when she wanted to share a thought with me.

Enjoyment of your twin sister or brother’s success
    Unfortunately, in childhood twins are subject to endless “compare and contrast” questions from onlookers and personal friends and relatives. So, giving up the idea that you should be the same and do everything the same is a hard struggle. The first ray of light in this identity issue is to respect your twin's accomplishments. Doing this seemingly simple action will build a strong adult attachment.

Communication Style Is Critical
    Intensity of thoughts and feelings make communication between twins very difficult. When jealousy and disagreement about family issues and opinions cannot be resolved then twins will have a great deal of difficulty developing healthy communication styles. In addition, acceptance of your twin's choices in interests and relationships is extremely crucial. If acceptance of differences are impossible then productive communication cannot be achieved. For example, I have talked with many twins whose sister or brother will not accept the new husband or wife. These twins choose to let everyone know and often do not attend the wedding. Maybe not attending your twin's wedding is hard to believe but it is true. It happens.

Conclusions
    You can get along with your twin if you understand the above ideas and try to keep them alive in your twin relationship. There are some communication strategies that seem to promote attachment that I have learned the hard way. I wish I knew then what I know now.
    1. Fighting with your twin whether physical or emotional is very hurtful and should be avoided as much as possible as it is hard to forget very mean comments.
    2. Spending too much time together breeds competition with your twin. Distance can be a very helpful way to promote respect.
    3. Not developing your own separate friendships creates boundary confusion. Let your twin have their own friends.
    4. Try to avoid comparisons as much as possible. Say to others who focus on your differences with your twin or imply that you should be more similar or get along better, “We are different people and don't want to be compared.”

The purpose of this twin group is to have twins learn about themselves by talking with other twins who have similar experiences being a twin in a non-twin world and by reading about the twin experience.

The closeness between twins seems to trump other types of very close interpersonal relationships. The twin experience is very different than the experience of siblings. More intense and susceptible to anger and resentments, twins face challenges with their co-twin and with others who idealize the twin relationship as profoundly affirming.

Twins face real challenges learning to get along with their twin. Nobody knows how hard it is to be a twin more than twins themselves.

Also, knowing that others have similar problems is a remarkably calming experience that allows for further reflection.

https://www.psychologytoday.com/us/blog/twin-dilemmas/202207/can-you-overcome-twin-loneliness