Don't respond. It reads like someone who is trying to assuage his guilt by appearing "reasonable" and as if this is a loving act. Really, (he's implying), I did this for YOU.
Bah! My guess is that when you met with him, he saw you looking confident and foxy and he didn't like that at all. This letter is a little poke to rock your world. After all, he's miserable, you should be too in his opinion.
Ignore the email. Do not respond. Picture your H with antennae and a weird alien voice writing this. It's just alien script and therefore has nothing to do with you.
When I was going through this, I gave my H the nickname Phantom of the Opera, and anytime the spew/script showed up, I'd hear the organ playing and sort of giggle to myself. Thinking of Alien H as PotO helped me detach and depersonalize it.
If he pressures you for an answer or ever brings this up in person, then your response is, "I can see how you might feel that way." There's no need to argue or defend; would you try to defend yourself against the words of an alien crazy person? He's the only one who believes it.
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!