THE LOVER OF HISTORY by Jonathan Dee (Ticknor & Fields: $19.95, 228 pp.) . First-novelist Jonathan Dee shows a nice touch with personal relationships in "The Lover of History," a story revolving around three young Manhattanites who have an uneasy alliance. Kendall, the engineer at an all-news radio station, shares Warner's apartment, but the relationship between the shapely Kendall and her asexual roommate (a history teacher, hence the title) is purely a matter of hard-headed economics. Kendall's lover, Julian, is a sexy and self-satisfied singer of jingles for radio and TV commercials. Relationships among the three become strained as each struggles to find some meaning to his/her life--a self-doubt that is exacerbated when the U.S. secretary of state is assassinated in a small and distant country.