um, well all I can tell you is hindsight. He was pissy about the scheduler intrusion. He then said something that would piss you off and you went for it. You probably shouldnt have hinted about the OW in your email to him.

What I think you should have done (and still may be able to with damage control) is make it an issue about boundaries and about your S.

"Several weeks ago you asked me to take him to class. I can understand if you want to do it to help me out, but we need to be more consistent on how we deal with issues, esp ones that concern our S. I dont need you to take him to class tonight; I have no problems doing it for you. How about we forget the heated email from before and just go with that, ok? I do appreciate the offer"

or somesuch.

Bill. "you are who you chose to be" - Iron Giant Link To CURRENT Sitch