On the other hand, a husband who always has been vigorous and assertive may suddenly become passive -- asking, psychologists say, for reassurance that his wife still finds him desirable. Or a wife may make sudden demands that she be courted, flattered or coaxed, simply because she needs her ego lifted.

In any case, Dr. Calderone remarks, such problems are a couple's own affair, and cann't always be measured by a general yardstick. ``As long as the couple is in agreement in their approach to sex, it makes little difference if one or the other dominates,'' Dr. Calderone declares. ``The important point is that both be satisfied with the adjustment.''

Other experts say, however, that if sexual domination by one or the other partner exists for longer than a brief period, it is likely to shake the marriage. And just as domination today often begins with the wife, so the cure generally must lie with the husband.

``To get a marriage back where it belongs,'' comments Dr. Schillinger of the Lincoln Institute, ``the husband must take some very basic steps. He must begin, paradoxically, by becoming more selfish. He must become more expressive of his own desires, more demanding and less' understanding'.''

Too many husbands, Dr. Schillinger continues, worry about ``how well they're doing,'' and fear that their success depends on some trick or technique of sexual play.