Is the sibling relationship the most enduring of all?

I wonder who the rare creatures who have managed to sustain a relationship for 60 years are. I'm amazed at the endurance of their love, but mostly I'm touched by their ability to peer through varifocals and see the bride or groom of their youth, to understand what shaped them, because they witnessed it all. Stories of friends who met at school and are still best friends can ruin me. It turns out that I am known and loved by someone for a long time.

I have a lot of old friends. Being in their company is one of my favorite things. I have been married for a long time, and sometimes I think of myself in 2061, clasping the dry, old hand of my husband and telling whoever will listen about our secret to a long and happy life together.

These relationships are magnificent, but they will probably not be the longest of my life or the most formative. My two sisters have been with me for 44 and 37 years. I can say I have known them for 83 and 76 years if I make it to 83.

A majority of us have a sibling. Our relationships with them are usually more lasting than the parent-child relationship. We don't choose them, in the way we choose a spouse or someone to get drunk in a park. Sharing your whole life with another person or people is an amazing thing to think about.

There are so many things that can go wrong with this simple generalisation. What about half- and step-siblings? We no longer speak to our siblings or those we have lost. When I started making Relatively, I thought about my own sibling relationships, which were not always easy. Our family doesn't fit the mold. I didn't know how many different ways the family unit could be put back together after a divorce.

The bonds I have with my two sisters have already lasted 44 and 37 years 

I didn't expect to discover that it could be all these things in family life. Gill Hornby put it well when she said that children in families that are not stable cling together like orphans in the storm.

I grew up eating Dutch milk and cheese while living in Holland. My parents separated when I was a child. They moved out of the family home. As a child, I believed that the splitting of the family was fair. My little sister was small and I hated the idea of Dad being alone.

Dad moved us back to the UK as siblings apart. Our sister came to see us when we traveled to see our mother. My parents did what they thought was best, and Dad did a great job of bringing up two teens, holding down a job. Lynn Barber once said that no one else understands the mess siblings come from.

Even in stable and regular families, siblings are still the keepers of each other's histories. Who else but your sibling holds the key to your family's secrets and memories, even if your children joyfully escape the traumas of divorce or death? Who else knows more about your imaginary friend, the dance moves made up in the living room, or how bad your makeup was during your goth phase? If not the other small people in your universe, who will remember the death of a beloved grandparent?

While the plots of favourite family folklore are often agreed upon, their edges smoothed and made comfortable by the process of telling and re-telling, there are hundreds of other stories that are remembered completely differently by each.

There is a contradiction about brothers and sisters. They have a lot of things in common: blood and DNA, one or two parents, a home and maybe a surname. Much is completely different. Twins or triplets are the only siblings that are actually born into the same family. Their arrival will always be different to that of their siblings. When I described Relatively to her, I said, "none of us swims in the same water." That matters. The scenery of your childhood will be different to that of your sister or brother's early years. Your parents might be rich or poor, living in a bigger or smaller house with elderly relatives still alive, or mourning the loss of a loved one. They may have more time on their hands. There are a million ways in which families change, all of which affect the development of each sibling.

My sisters and I were only together for a short time, and after that there were very few experiences that we shared as a trio. We often got together for Christmas or summer holidays, but we missed out on the mundane glue of arguing over the remote or who finished the last of the cereals. We didn't get to nurture the true sibling familiarity that comes from spending lots of unremarkable Sunday afternoons mooching around the house together. There was a lot of space between our realities. Splitting the family between Holland and England made the differences more marked. In the UK, my sister and I were at schools that were very similar to the Malory Towers era. Kids who grew up in a modern international school are unrecognisable. We were parented in many different ways. My older sister and I were more independent than my little sister. The free-form set-up in the other house was at odds with the absolute domestic order and maternal scrutiny in the other.

I remember Mum on the phone, utterly exasperated when my little sister had returned home with yet more clothing missing

When my sister returned home with more clothing missing, I remember my mother on the phone. She couldn't comprehend a world where socks and T-shirts got lost. I could. She was still a little girl when I and my older sister were teenagers. I am sure she was confused as well as left out. It usually takes a lot of stitches to knit siblings together.

We began to tell each other about the years spent apart from our own point of view as adults. Talking about these events with my sisters makes me feel like I'm in a weird place as I try to see different scenes from our childhood. Growing up apart had an impact on our relationship with our parents. As sisters, we are sometimes curious about what it would have been like to have the other parent around, and I suppose I missed my mom as a teenager. There is no point being envious now, but from time to time we talk about what if.

It is also a kind of delight. Our reflections on the childhoods we had help us understand how we relate to each other as adult siblings. I need this kind of tethering to my past to feel understood as I get older. As I begin the third season of Relatively, I look forward to hearing these kinds of conversations with a whole new set of brothers and sisters.

relativelypodcast.com