I haven't sent any email about our activities, but based on the feedback I'm going to rethink what I was going to send. My intent was to let her know that life goes on without her, and we're having a good time regardless.
You're doing fine with being a bit mysterious and detached. Stick with that theme. Like the others said, SHOW her detached, don't tell her. Since you're in pseudo piecing you don't have to be dark or anything, you might text her a pic now and then of the kids doing fun stuff like surfing