That decision has been made.

You can’t change the past.
No.  
Really, you can’t.

No amount of rehashing, rethinking, what iffing, replaying the conversation, 
blaming, playing the victim, or brilliant come back you’ve now thought of
will change what happened a minute, month or years ago.

It is perfectly okay, legitimate and a good idea to consider the consequences
of past actions.
But only if you let what you learned from the situation inform how you might
respond now.

Get out of the past.
Be present with who and what is going on in your life today.
Right now.
Minimize the time you spend looking in your personal rear view mirror.
You’re not going that way.

(Clearing mental clutter is as important as clearing physical space)