Gosh. Does Simmonds intend to update Gustave Flaubert's Madame Bovary? Her heroine is unhappily hitched and quick to cuckold her dull husband (also named Charles), while a nosy neighbor cites Flaubert's original ad nauseam. But the resemblance stops there. Where Emma is at turns insufferably selfish and hopelessly tragic, modern-day Gemma is a snore, a Bridget Jones knockoff prone to penning such ridiculous diary entries as ''How can an affair be bad when it makes me feel so good?'' Oh, how about when said affair ends with her untimely death at the hands of . . . the Heimlich maneuver?