Poisonous friendship?

I have had a freindship (a very strange one) for several years with a girl I met in high school. We were very close, but something would always go horrendously wrong and we'd been pretty not happy with each other. We've been out of high school for 6 years now, and we do talk on the phone now and then, and email regularly. She is moving back to where I live in the middle of the summer. My question is, should I avoid interaction with her or not? I have never had such a close friendship in my life, and in all honesty she is one of the only friends I have ever actually loved, but she ALWAYS, ALWAYS does something to severly hurt me. I mean she is a very thoughtless person. What would you do? Thanks.