I think you should send the letter because it puts you back in your power and sets some boundaries. Dan keeps beating you up because you take it. It's time to kindly, unemotionally shine the light of truth on his B.S. Your tone and everything in that letter was very even, just the facts. Nothing wrong with saying your piece. Just detach from the outcome, and say it for yourself, not because you think Dan will (or won't) react in any particular way.

SD

Me: 40
H: 43
H had EA from 2/06-9/06
Bomb 5/06
Piecing since 9/2006
3/2008: Boundary setting
7/2009: Boundary crossing~dropped my own bomb.
8/2010: Marriage finally on track!