That email could have been written by either male or female. I don't see a gender slant in it anywhere. It does tell me that H is not shouldering any blame for the demise of your M. It is a very selfish letter stating what he sees as facts. If his thoughts were always the same (ref: we never were) then why is he now talking about what is acceptable to him and from my point of view, expecting an apology and changes to come from you instead of him. He wants to take everything back to before you met and if you are not willing to change, he can walk away telling everyone that he offered an olive branch to you. (a very dirty second hand one)
He tried the "I need help with my therapy" angle, that didn't work, you didn't fall over and beg him to come back last time you met, so this is his next shot across the bows.
I don't see anything changing even if you never respond to this at all. I feel he will think for a while and then come back with another try.
How does it make you feel Kass?. I ask that, because I see it as an attempt to break you into taking the blame or becoming harder and colder towards him so he can tell everyone how you acted.
Keep swimming Kass, there's a shore out there somewhere with your name on it!