LOVERS AND TYRANTS
by FRANCINE DU PLESSIX GRAY
316 pages. Simon & Schuster. $8.95.
Francine du Plessix Gray, 46, is a tall, blonde woman with large eyes and elegant cheekbones. The daughter of a French aristocrat and a White Russian emigré, she lived in Paris as a child, moved to the U.S. in 1941, went to a fashionable New York girls' school (Spence) and Barnard. After college she had a fling in Paris, then returned home and settled down to life in the country with her painter husband and two sons, now 15 and 16....