What’s the classiest way to end a conversation with a rambler?

I seem to run into this more and more as a 30-something woman. I seem to be a beacon for attracting people who hold me hostage in a conversation where they’re telling me their life stories or deeply personal experiences (TMI stuff). I am an empathetic person but I need to learn how to set better boundaries in this area, so I’m wondering how you classy ladies end a conversation with people like this?