My T was telling me that we're attracted to people who in some way represent the people with whom we first were attached - our parents or early caregivers. It doesn't matter if the experience was pleasant or unpleasant - we still gravitate to those types.

She has pointed that out to me in my own relationships and it rings true. There is a whole theory around this that I can't express right now. I'll look it up and share it with you later.