"Fuck excuses, learn to admit when you fuck up." This includes trusting the wrong people (and subjecting yourself to abuse). If you never admit you're involved, the same shit will happen to you, ad infinitum.
Quite possibly, this is the cruelest thing that you could do to someone. Particularly when you don't understand it or only know part of the truth (at best), anyway. Let people live; let people learn. (Those are not my words but well said.