Every time I hear the song “Long Black Veil,” I wonder the same thing:
Is that outcome really preferable to the alternative?
(I'm going to use male pronouns to refer to the narrator and the best friend, for simplicity, although we don't know the best friend's gender for sure.)
To recap the story: The narrator was accused of murder, due to mistaken identity; at the time of the murder, he was sleeping with his best friend's wife; but he declined to provide that alibi to the court, presumably to protect his lover, and so he's put to death, and now his spirit watches as his lover wanders around at night in a long black veil.
So let's look at what happens to each of the characters in the song:
The narrator ends up dead. Not ideal.
The narrator's best friend ends up presumably believing that his best friend is a murderer, and knowing said best friend has been executed, and not knowing why his wife goes out late at night dressed in a black veil. Is this really a better outcome for him than learning that his best friend and his wife had slept together? I mean, that would probably be really bad, but would it really be worse than what happens in the song?
The wife, who also declined to speak up during the trial, manages to keep her cheating secret, but her lover gets executed (which I would expect would make her feel pretty guilty) and she has to spend her nights wandering through the hills and the graveyard in a long black veil, and she has to continue to keep a secret from her husband.
And the wife and the husband probably have to endure everyone else saying that their lover/best friend was a murderer.
And the witnesses and judge and jury fail to learn an important lesson about the unreliability of eyewitness testimony.
Oh, and also? The actual murderer is wandering around free.
Sure, you can come up with all sorts of explanations. Maybe revealing the secret would put the wife's life at risk or something. But in a straightforward reading of the song, I find it hard to say that the outcome they end up with is better than what would've happened if the secret lovers had revealed the truth. I mean, if we're gonna add stuff beyond what's in the song, we could just as easily go the other way and say that the husband has always secretly wanted to be in a triad with the other two, and if only they had spoken up, they could've all lived happily ever after.