Can you talk this through with a counselor? I haven't been in this situation, but if maintaining a distant/cordial relationship is too much, maybe you could slow it down even more. Take it down from 3/4 emails a year to 2/3 and visits maybe once every year or two. The longer you go without communicating the less stress to deal with. And maybe what you need more is learning how to detach and not let them take up space in your head in between communications. It would free up that negative energy for those who truly do care for you. A counselor could help you with that.