I'm no expert, but thought I'd chime in with the observation that most of what I've been seeing others emphasize in DB is that it is fruitless to challenge the spouse's version of reality or what has been happening in the M. My sense is that you would be best hanging on to your response as a personal journal item and just respond briefly to her to acknowledge receipt. Something like: "I'm really sorry you feel that way. I've had a real wake-up call and know that you and our marriage are very important to me. I've learned a lot and am committed to continuing my own growth. We can talk more when I get back from work." Maybe you could broach the topic of MC, even if just for working out the co-parenting issues. But, I would try to keep email discussions to a minimum.
me: 47 H: 48 he has 2 grown sons M 1995(my 1st, his 3rd) hit iceberg 6/07 S 9/26/07 before now