I didn't like the first part rehashing how his affair began, but it picks up speed when you start talking about yourself. Starting about with " My love was for this good man who I was priviledged to share my life's journey with...." except you could say that you thought you were priviledged to because actually, it didn't turn out that way. I think you have gotten into the meat of the matter.
And yes, if he doesn't answer the question, I have been thinking for weeks that he was trying to get you to commit suicide. I know it's a terribly ugly thing to say. But you had me so scared sometimes. There were at least 2 saturday nights I barely slept worrying about you. So it needs to be said. I believe you would have fulfilled his desires if you had simply taken yourself out of the picture, whether by leaving or committing suicide.
I think the letter is a home run. I would send it without the first part.
