I am getting ready to go to Plan B for my own recovery now. But I want to hint at the possibility of recovery. I cannot write a love letter at this point - to much hurt and betrayal. But here is what I have so far, with help from others who have been following my thread.
Thanks for any assistance!

Plan B letter:
WH,
I have always admired your integrity, caring, and reliability. Your strength has always inspired me. I will remember kindly all the times you have stood by me in bad health, in difficult times with the kids, and in other difficulties in our lives. I will also fondly remember all the fun times in PIB, Vegas, and the Smoky Mountains, the long walks on the beaches in Florida and the Bahamas. But I will mostly remember good times with kids. DSD20 and I have forged a friendship and bond that will last a lifetime.
I have also always believed in you, trusted you and loved you.
Since you continue your affair with OWH"S wife I need to avoid seeing you or talking to you. You may contact me through your mother, sister, or my brother. I ask that you respect my decision to separate from you this way. You must understand the suffering that I have endured because of your continued contact with her and the choices that you have made that have affected us both and our family. I simply cannot be around you any longer knowing that you continue to see her. I cannot live with you under these circumstances.
I will always believe in second chances; and I still believe that this relationship can be salvaged. I loved you when I married you; and deep in my heart I love you still. Please remember that there may be a path back home.
I simply cannot be around you while you continue this affair.
Mymissy

The more input the better - I am moving in 25 days.

This is my opinion.

1. Add a paragraph where you own your part in this issues. Admit his complaint about you that weren't just excuse for his A. Give hope that it will be change or refer back on your plan A.



2. Make it stronger. not "may be".

-rh-

Ok, here is a slightly earlier version:


WH,
I have always admired your integrity, caring, and reliability. Your strength has always inspired me. I will remember kindly all the times you have stood by me in bad health, in difficult times with the kids, and in other difficulties in our lives. I will also fondly remember all the fun times in PIB, Vegas, and the Smoky Mountains, the long walks on the beaches in Florida and the Bahamas. But I will mostly remember good times with kids. DSD20 and I have forged a friendship and bond that will last a lifetime.
I have also always believed in you, trusted you and loved you. I am sorry for my part in creating an environment that helped make your affair with OWH's wife possible.
Since you continue your affair with his wife; I need to avoid seeing you or talking to you. You may contact me through your mother, sister, or my brother. I ask that you respect my decision to separate from you this way. You must understand the suffering that I have endured because of your continued contact with her and the choices that you have made that have affected us both and our family. I simply cannot be around you any longer knowing that you continue to see her. I cannot live with you under these circumstances.
I will always believe in second chances; and I still believe that this relationship can be salvaged. I loved you when I married you; and deep in my heart I love you still. Please remember that there is always a path back home.
I simply cannot be around you while you continue with this affair and to behave in this manner.

I think it is important to add a line about the path back home would include the commitment to no contact of any kind for life with the OW, and the measures to insure no contact being followed.