Use dictionaries, encyclopedias, and handbooks to learn quickly about the state of research on your topic. A good encyclopedia article should describe major themes, current research fronts, and controversial areas; it should also provide a brief bibliography of classic, important, or definitive works on your topic. Handbooks generally offer chapters on specific aspects of a topic: together, the handbook's chapters should provide a broad overview of the state of research; individually, chapters may be narrowly focused.
See especially "Cognitive, emotional, and sensory functions" and "Personality and interpersonal processes". Representative articles include: "Attachment and bonding", "Friendships", "Romantic Competence", "Love".
The 12-page article, "Close relationships", is one of several useful articles in Vol. 5, Personality and social psychology.
Of particular interest: The Social World's 43-page article, "Close relationships".
Literature reviews are a handy way to get quickly into the scholarly literature. A typical literature-review article will provide a narrative that identifies and describes dozens of journal articles and books.