The reclusive man who marries the gregarious woman, the timid woman who marries the courageous man, the idealist who marries the realist - we can all see these unions: the marriages in which tenderness meets loyalty, where generosity sweetens moroseness, where a sense of beauty eases some aridity of the spirit, are not so easy for outsiders to recognize; the parties themselves may not be fully aware of such elements in a good match.