Passionate love, also called infatuation, is "a state of intense longing for union with another. Reciprocated love (union with the other) is associated with fulfillment and ecstasy; unrequited love (separation) is associated with emptiness, anxiety, or despair",[1][3] and "the overwhelming, amorous feeling for one individual that is typically most intense during the early stage of love (i.e., when individuals are not (yet) in a relationship with their beloved or are in a new relationship)".[4]
Companionate love, also called attachment, is "the affection we feel for those with whom our lives are deeply entwined",[1][3] and "the comforting feeling of emotional bonding with another individual that takes some time to develop, often in the context of a romantic relationship".[4]
Evolutionary theories suggest these two types of love exist for different purposes, and research from psychology and biology suggests they follow somewhat different mechanics.[5][6][7] Both passionate and companionate love can contribute to relationship satisfaction.[7][8] Passionate and companionate love can also be further distinguished from a third important type of love, compassionate love, which is love focused on caring about others.[7]
Passionate love is also commonly called "romantic love" in some literature, especially fields of biology, but the term "passionate love" is most common in psychology.[6] Academic literature on love has never adopted a universal terminology.[2][9] Other terms compared to passionate love are "being in love",[7][1][5] having a crush,[1]obsessive love,[1][7][5]limerence[1][10][5] and eros.[7]
Companionate love is commonly called "attachment"[11][4][6] or compared to strong liking, friendship love or storge.[7] This is usually considered the same as the "attachment system" from attachment theory, but not all authors agree.[12][6][7]