I know that I was emailing stuff to my wife because I was afraid to do it in person. Perhaps your wife is the same? It was a mistake on my part, as it just aggravated her and made her feel that I was trying to provoke her. It didn't help that it was usually after a discussion where she thought I had agreed with her. I need to be more clear about validating, and when I'm not sure about something, tell her that I need some time to think about it.
