IT'S NO accident there are so many metaphors for love having to do with food, and no wonder so many recipes have been tried out as aphrodisiacs. The twining of food and love goes all the way back -- to the apple, or to the breast, depending on whose theory you follow.

(The corollaries of this relationship, if memorized, might prevent you from contracting yourself to an unsuitable partner. Remember, for example, that an insensitive eater is likely to be a graceless lover. A lack of imagination in the one art reflects a similar lack in the other. And gulping food is certainly rusing things.)

As an adult, in the loose sense of the word, you must accept certain responsibilities toward your Significant Others. Cooking for an S.O. requires the same maturity and tact as having an affair. A parked car may be great fun when you're young, but adults need more room -- or they may need traction.

So grow up about entertaining. Thin out your file of lasagna and get rid of any recipe with "surprise" in the title, or that requires canned tuna, catsup, frozen peas or cream of mushroom soup.

No corn flake toppings. No Minute Rice. Nothing from a cardboard box intended to be combined with a pound of ground beef.

Nothing that says, "just add water," "imitation chocolate" or "non-diary." Nothing that is advertised by a disembodied hand or animated oven mitt. No dancing dough and no singing salad dressing.

Nothing lighter than air or homogenized enough to be spread with cardboard. Nothing "krisp" or "qwik." No eggs that weren't laid by a bona fide fowl. No cheez, no pre-whipped topping.

Nothing, in short, that fools Mother Nature: Like Hebrew National, we have to answer to a higher authority.

Love, first of all, is not blind. So remember that certain green vegetables have a tendency to linger around the teeth, and that barbeque sauce makes your fingernails black.

Neither is love Superman. A turmeric delight may make his heart burn with more than affection, and too many bottles of even the highest character may sabotage the entire evening's entertainment.

Finally, love is not cool, and neither is Washington in July. So make her an offer she cannot abuse -- a cold fettucini primavera with seafood, crusty-hot French bread and cold white wine. Oh, those summer nights. YVES COLD FETTUCINI WITH SEAFOOD

Pick out three or four of the day's best and prettiest fresh vegetables: broccoli, peas, green beans, zucchini, tiny eggplant, mushrooms, snow peas, (you don't need a whole lot of any one thing). Also pick up a red or green sweet pepper and a red (purple) onion, a ripe tomato and a bunch of fresh basil or dill.

You can use any light seafood you choose: shrimp, lobster, crabmeat, even softshells. If you want to go deluxe, add crab claws or red caviar.

You will also need a fettucini, white wine vinegar, sour cream or mayonnaise, salt and white pepper, and a chunk of parmesan cheese.

Slice the raw mushrooms and pepper and quarter a couple of slices of red onion into bright, bite-sized pieces. Cube the tomatoes (skinning is optional). If possible, cook vegetables and seafood ahead of time so they can chill. Slice green beans on the diagonal, cube the zucchini and eggplant, and separate the broccoli into tiny flowerettes, saving the stalk for some other day. Boil the vegetables separately, none for more than a few minutes; you want them to be crunchy. Drain into a colander, rinse with cold water and drain completely.

Don't overcook the shrimp, either; overcooked, it will be rubbery when cold. Boil and pick the crabmeat or lobster.

For the dressing: season the sour cream or mayonnaise to taste with the vinegar, salt and pepper. Finely chop the herbs and stir in. Grate the parmesan and set aside.

Break the pasta in half, cook only al dente, rinse with cold water and drain very well. Combine the chilled vegetables and seafood in a large bowl and dress. Add the pasta, more dressing and toss again. Sprinkle caviar over the top or surround with crab claws. Serve the parmesan separately.