Claire, if it's a short apology letter, and you say that you don't have any expectations from it but that you need to do it in order to move on, then I think *in your instance that it would be helpful.
You're really not doing it for him, right? But just for yourself?
I'm so sorry for all that you have been missing. I wish I could wave a wand and make things right for you. But he's clearly a fool, you are worth making an effort for. May you be loved with all the strength with which you give love.
Whether it turns out to be him or someone else.
*for all the newbies reading this thread and thinking it's a good idea, IT'S NOT FOR YOU. This is for Claire whose situation is different.
Me42, H40 D12, S8, S7 A revealed: 7/13 Sep 4/14; Agreed to D 1/15