Mending a deeply fractured relationship with a sibling?

[Avienus]

I am in my mid-thirties. My slightly younger (and only) sibling and I have always had a difficult relationship, but this blew up into an almighty row prior to the birth of our first children (separated by only a few months).

There began an extended period of estrangement - I did not meet my nephew until he was four. Since then, relations between us have varied from tolerable to barely civil. Right now, we ignore each other when we meet, which thankfully is not often as I live several hours from my mother so only see my sister when I am visiting there.

I acknowledge that I have behaved badly at various points over the years. I feel more sinned against than sinning, but I am aware that she feels similarly.

I dislike her - I do not want to be her best friend, nor anything approaching this. I do, however, want to stop the cold war that is now dragging into its seventh year. My reasons for this are: I feel embarrassed that I am Not Talking To someone, like a spoiled child; the situation is painful for my mother; it would be easier and more pleasant for everyone if there was civility.

Do you have any practical advice for achieving this? I am aware that I must sound deeply immature and lacking in social skills. In my defense, in other parts of my life I have warm, empathetic and healthy relationships. I really don't know how to behave like the adult I am in this situation as my feelings are so raw and ancient patterns of behaviour are so hard to break.

........and neither of us would ever get anything positive from attempting to have close contact.......

Then I wouldn't bother.

To make life better for the kids and your mother, I would maintain the social niceties - birthday/Xmas cards and presents to her - along with a civil greeting - and birthday/Xmas cards and presents to the kids. Otherwise, just keep yourself out of her presence with a 'Hi and Bye' eg by going to the next room to do some task, going to the shop, raking up leaves .......whatever.

That should be enough to keep your Mum happy and persuaded that things are improving (which is, I think, the best you can likely achieve) - and the childrens' relationship with you and yours will be more or less maintained by the cards and presents. You are, after all, some distance away from them and they're only young.

Does she live near your mum? Is it possible for you to visit your mum without seeing her?

Otherwise I'd advise just making polite conversation and leaving it at that. Don't apologise if you feel you've done nothing to apologise for. Don't expect an apology. Treat her as you would your mum's next door neighbour.

If rebuffed, it might be simplest to withdraw, in a dignified way: if only on the basis that she's not ready to mend fences yet, even if you are (not much you can do about that).
Or you can respond more assertively. It's a question of what you think will work for you