You decided about it and said nothing
The Libra half of this is common material across a whole span of birth years and reworks how people arrange themselves with one another; the twelfth house, decided by your birth hour, is what keeps it out of sight.
Remember the last time you concluded that an arrangement was unfair and let it stand. That is the pattern here: an accurate private assessment, complete and unstated, held indefinitely while everything continues as before. The judgement is usually right, and nobody has ever been told it exists.
Everything is weighed and nothing is declared
You are continuously assessing whether people are being treated properly — in your household, at work, in every group you sit in — and almost none of it is voiced. The assessment is not idle; it changes what you do. It simply changes it silently, so nobody around you can tell that a position is being taken.
Keeping the peace is done at your expense
The way you protect a group's atmosphere is by absorbing the imbalance yourself, and it works, and there is nobody absorbing yours. The arrangement is invisible because you built it. Saying one thing out loud that you would normally hold is what tests whether the peace actually depended on your silence, and it usually does not.
Read as easy-going, running on a strict standard
People conclude that little bothers you, because so little of what bothers you ever surfaces. What is actually operating is a demanding sense of how people ought to behave, applied constantly and privately. Stating the standard occasionally, without an incident attached to it, is the only correction, and it will surprise people considerably.
A private record of what was fair
What accumulates here is an accurate account of who has behaved well and who has not, across decades, that has never been shared with anybody. It informs everything you do and is entirely undocumented. Saying one item of it to somebody, once, is worth doing, because a verdict nobody has ever heard cannot be checked and starts to feel less certain than it is.
You have been arbitrating with nobody appointed
For as long as you can remember you have been quietly deciding what is fair and adjusting your own behaviour to compensate for other people's failures to. It is an unpaid and unwitnessed office. Recognising it as work you have been doing, rather than as a temperament you happen to have, changes what you think you have spent your life on.
You leave a friendship without an argument
When somebody has crossed a line, you do not raise it; you simply become gradually less available until the friendship has ended, and they frequently never find out why. It is a clean method and an unkind one. Saying the actual reason, once, even after the fact, is worth more to them than the years of politeness were.
You already know how it would end
Somewhere in you there is a fully worked-out account of how this relationship would come apart, assembled quietly and never referred to, and it has been sitting there since fairly early on. Holding it is not the same as wanting it. It does mean part of you has been rehearsing an ending for years while the rest carries on. Saying that out loud, absurd as it sounds, tends to dissolve most of its power.
You saw how it was arranged and never said
You understood early which member of the family was favoured, who was carrying what, and what everybody had agreed not to notice, and you kept all of it. The accuracy was not welcome then and would not be now. Writing it down privately, once, is a legitimate use of an observation that has nowhere else to go.
You absorbed the unfairness rather than reporting it
In working life you have taken on other people's shortfalls, covered for arrangements you thought unjust and said nothing, sometimes for years. It kept things running and it also meant nothing was ever corrected. Naming one thing to one person with the authority to act, without making a case of it, is a smaller act than it feels and it is the only route to any change.