A huge part of love, whether that love is romantic, familial, or otherwise, is being able to trust one another. And a pillar of trust is transparency — having nothing to hide, and hiding nothing. Being an open book. Sharing all that you are with another person. Establishing a sense of predictability.
The way I see it, if sharing difficult information is going to upset someone, it’s the source of information and the person it stems from that are the cause of that pain, and not me by being the one relaying it.
And this sort of thing will come out eventually.
So when it does come out, and my partner or sibling or friend or whomever finds out I’ve known about it the whole time and not given them them the courtesy of a head’s up, I’m no longer honoring the integrity of our relationship and being transparent.
Just because I didn’t want to be involved in a situation, doesn’t mean I can deny it once I am. By staying out of it and pretending I didn’t hear anything, I’m lying to myself and to the person I care for.
If I have knowledge of the event, whether or not I’m the one initiating it, and irrespective of the fact that it’s against my will, I’m still involved. I can’t change that fact, but I can decide what to do about it.