If the concern is truly about the female 'friends' husbands, then I agree with Ian. It isn't your responsibility to worry about what other females are doing with or without their husbands knowledge.
However, if the concern is that you don't wish for your Dom to be receiving (and viewing) these types of emails, then that's another issue entirely, and you'll want to communicate your feelings with him so that he isn't unknowing hurting you.