Fault Has Nothing To Do With It
So many times arguments are created between people all in the name of "fault". My theory is that fault came to be when people wanted to avoid dealing with their actions or to avoid getting in trouble. The reality is that the mindset of "fault" is fine for children but as you grow up to be a big person shouldn't "fault" no longer be an issue.
Adults don't have to prove or explain their actions but that's often confused with not being accountable. What you choose to do is totally up to you but what it does or how it affects other people you have to "own" too. "Own" doesn't mean care, it means that you can't act and not deal with the reactions of your actions. You don't exist in your world by yourself! Acknowledge how your actions not only affect you but those around you.