The newlyweds George Gaylord Simpson (palaeontologist) and Anne Roe (psychologist) travelled through Venezuela on an expedition in 1938–39. The result was intellectual work unlike anything each did elsewhere in their long careers. Romantic and intimate partnerships offer fascinating case studies of collaboration in science. They produce unusual intellectual synergies. They alter life–work patterns. They simultaneously constrain and liberate. These collaborations tend to be overlooked by historians and biographers of science, leaving us with vastly inferior knowledge of science as a living, working enterprise.