"In a relationship, one mind revises the other; one heart changes its partner. This astounding legacy of our combined status as mammals and neural beings is limbic revision: the power to remodel the emotional parts of the people we love, as our Attractors [coteries of ingrained information patterns] activate certain limbic pathways, and the brain’s inexorable memory mechanism reinforces them. Who we are and who we become depends, in part, on whom we love." - A General Theory of Love by Lewis, Amini and Lannon
Read more about A General Theory of Love, as well as four other books that tackle the psychology of love, at Brain Pickings.