Why men cat around and what--if anything--women can do about it. Botwin (Is There Sex After Marriage? 1985; etc.) reluctantly accepts the possibility that males may be genetically predisposed to multiple partners. She cites two inconclusive experiments. One revealed that male rhesus monkeys lose libido when forced into monogamy, but will copulate enthusiastically with a second female introduced to the cage. The other showed men to become progressively less sexually aroused when a series of pornographic films featured the same cast; but they perked up when a new cast was introduced. Women had the opposite response. Botwin still contends, however, that women should expect fidelity from husbands and long-terms lovers. She provides a query, with patently obvious questions, to determine infidelity--""Is sex different?"" ""Are there strange phone calls?""--and a dovecote of pigeonholes for womanizers: ""Obsessive-compulsives,"" ""He-men,"" ""Rebels,"" etc. Some women, she says, cause or collude with their man's roving: they don't like sex; they enjoy the ""mommy-daddy"" drama of straying and forgiveness; they are willing to ignore infidelity when their man is rich and powerful. When a man strays, Botwin suggests you communicate and don't scream; don't hop into bed with someone else or dump on your rival; but try to change yourself and work out the problem with your partner. If all else fails, consider splitting. Other than being less acerbic towards men than Botwin's previous work, there's little that's new or to recommend here. Still, women seeking solace and advice may flock--without finding much of either--to this one.