When all the men say ""Good god"" and all the women say ""But sweetie,"" you know--alas--that you're stuck inside another of Spackman's fluttery, precious little pastiches of ""civilized"" love and sex. And, like its predecessors (An Armful of Warm Girl, A Presence With Secrets, A Difference of Design), this paean to the joys of adultery is heavy on chirpy dialogue and chichi trappings, light on anything like characterization, substance, or genuine style. The meandering focus here is on four related couples, only one of them married. Incorrigible rake Scrope Townshend, a 60-ish, Spackman-like novelist, is still more or less in love with veteran fashion-mag editor Laura Tench-Fenton--his partner in extramarital bliss through various decades and marriages. (""With two loves you grow tired of neither. . ."") But now, though planning an amorous reunion after Scrope's recent heart attack, the oldsters are distracted by goings-on amid the younger generation. Scrope's daughter Sibylla (author of opera libretti) is married to Laura's stepson Alec (handsome, large ""modern poet""). Sibylla, however, is gradually falling in love with Classics prof Charles, who lives with fiction-writer Amy. And the fourth couple--spouting labored youth-talk while coupling in Princeton dorms--consists of Scrope's grandson and Amy's younger sister. Eventually, of course, Charles persuades a slightly hesitant Sibylla to embrace dalliance. (""What is this fuss!--it isn't as if we suddenly love Amy and Alec in the least less!"") Meanwhile, there are giddy chats about May-September liaisons, about the sociology of adultery, about Paris and Tolstoi and Henry James. The men remain clubbably faceless; the women--despite their supposed literary heft--remain interchangeable Cosmopolitan Girls, (""Am I your very dearest frantic-over-decisions sweetie or aren't I?"") And though Spackman's latest is sure to be welcomed by devotees of mannerism and camp, most readers will recognize this for the empty literary-boutique item it is.