When she engages you about what you did or didn't do:
"W I know I made mistakes. I recognize them. Our M is very important to me so I am taking a hard look at what I contributed to OUR situation. The path is open if you desire to work on our M."
That's it. STFU (shut the F@ck Up)
The rest you must show her, not tell her. She has heard words from you for a while before she left so they mean nothing.
Then.
Let her go.
If you can't deliver that message with the most sincere compassion and honesty then don't do it.
Wait until you can.
My goal is to some day be the person my dog thinks I am
