I read your sad post seveal times and noticed that there is a lot of you...but no discussion of asking her anything...
You "sat her down" , you "told her", you "decided" - did you listen or ask?
Is it really too late to try and talk? Perhaps simply asking her how she feels can open up a conversation.
I could not end a relationship with my mechanic as clinically as you seem to be ending your marriage.
Sorry if this comes off as unsympathetic, but I just don't see or hear any conversation, just what sounded like an ultimatum from you.