I believe that the more self love and self acceptance and self awareness of our aspects we have, the less we project to other people. At that point, love is just love, there is no need for them to complete anything in us because we'd be whole ourselves.
Practically, that is a difficult if not impossible place to get to.
So when you become aware of a projection on the other person, pause and take it in and try accepting them for the trait they really are. Maybe you'll learn about yourself along the way.