I think you are being too hard on yourself. I don't think you can mess with other people's boundaries unless other people complain; they get to set their own boundaries, not everyone's is the same, and it sounds like your psychiatrist is happy and able to answer your desire for e-mail contact. If it helps you and you both are in agreement about it, don't sweat it but by all means discuss it with him but ask him how he feels about it, don't assume you have crossed his boundaries.