DEAR ABBY: I am the executive secretary for the president of a large national company. My office overlooks the entrance to the building, so I see everyone who enters or leaves. A few months ago, while standing at my window talking to a male staff member, I saw a woman I'll call "Lois" leave the building, get into a car and leave with the driver. I commented to the staffer, "Isn't that nice? There's Lois leaving for lunch with her husband." The man replied, "That's not her husband; that's her latest boyfriend."

Abby, I have seen Lois leave and return in that car at least twice a week for months. I assumed it was her husband because she has kissed this man goodbye right outside my office window on many occasions.

The staffer then told me about the affair he'd had with Lois that nearly ended his marriage -- and I believe it, because a few days ago I spotted her leaving with the man again and followed them. I now regret it because I was appalled at what I saw when they parked in a remote area. She began undressing in the car!

Most people think Lois is a loving wife and mother. She is liked by her manager and co-workers. Should I go to human resources and report this? What if they don't believe me? How will this reflect on me? I see her in-laws in church every Sunday and at church functions. Should I just sit back and not mention the immorality?

My heart tells me to act one way; my head tells me it could affect my job in the long term. Please advise, but don't reveal my name or location. -- BETWIXT AND BETWEEN IN CORPORATE AMERICA

DEAR B AND B: Listen to your head. Lois is doing her job and has the respect of her supervisor and co-workers. For you to have followed her on her lunch hour was a mistake. You are not the local representative of the ministry of virtue and vice. If you report this woman's marital infidelity, you will earn the reputation of company busybody.

Sooner or later, Lois' affair will come to light. However, her private life is none of your business -- and if you are wise, you will not make it so. If you feel morally obligated, the person you should talk to is Lois.

Your letter brought to mind another one that appeared in the column years ago:

DEAR ABBY: We work in a large office. Our office manager -- I'll call him "Marvin" -- is a middle-aged family man. The boss's secretary, "Sissy," is a shapely young divorcee. Since Sissy came to work here, she and Marvin have been spending a lot of time together in the file room with the door locked. What they do in there is their business, but we're tired of covering for them when the boss comes looking for Sissy. What do you suggest? -- THE OFFICE GANG

DEAR GANG: Next time the boss comes looking for Sissy, tell him to look in the file room under "Marvin."

DEAR ABBY: I am going to a fund-raising party held in a park in San Francisco. The invitation says the dress is "casual sheik." Do you have any idea what that means? -- LOST IN S.F.

DEAR LOST: Unless the theme is Middle Eastern, the word should be "chic." In this case that means the dress should be "dressy casual."

For everything you need to know about wedding planning, order "How to Have a Lovely Wedding." Send a business-size, self-addressed envelope, plus check or money order for $5 (U.S. funds only) to: Dear Abby, Wedding Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: Last year, our family started a tradition I hope lasts for generations to come.

Each June on the Sunday before Father's Day, we plan to celebrate "Siblings' Day." We picked this day because it's between Mother's Day and Father's Day, and the kids are out of school.

Our children made cards for each of their brothers and sisters, telling each other what they liked about them and how special they are. Then I took them one at a time to the toy store to buy each sibling a present with their allowance. I was sure they would not want to spend their own money on each other, but I was wrong. Not only did they want to, but they put a great deal of thought and effort into picking out toys they thought each child would want. When we got home, the kids excitedly wrapped their gifts.

On Sunday morning, the cards and presents were exchanged. I made a special lunch and baked a cake for the occasion. The good feelings among our children lasted for days and were a delight for all of us.

Abby, I hope your readers agree that this special tradition could benefit families everywhere. -- A.H.C. IN ATLANTA

DEAR A.H.C.: What a lovely idea. We hear so much about how destructive sibling rivalry can be. Your positive approach to building a stronger bond among your children will benefit everybody later on.

DEAR ABBY: I read with amusement the letter from "Looking for Help in Pennsylvania," who wanted family photos that included her husband's ex-wife taken down from her mother-in-law's living room wall. Here's how I handled a similar problem.

My husband and I have two married sons. In 1985, the six of us attended a family wedding, and while we were all dressed up, I asked the photographer to take a family picture. Thinking this would be a nice tradition, we had another group portrait taken the next year.

I started a "family wall" in our den with the two portraits, but when it was time for the next one, our younger son and his wife had gone through a nasty divorce -- so, of course, "she" was no longer in the picture.

One day, while looking at the first two family photos that included our ex-daughter-in-law, I decided they were too good to hide or throw away, so I pulled out some acrylic paints and painted over her using a floral pattern. In the first picture, I call the flower "Venus Man Trap." In the second, "Blooming Idiot."

Since that time, our older son and his wife have blessed us with two precious grandchildren, and our younger son has married a wonderful girl we all love. We continue our tradition of taking an annual family photo. It's a wonderful way to see how we've all grown through the years. Thanks to my artwork, the older pictures aren't offensive to our new daughter-in-law. -- AMATEUR ARTIST IN ROME, GA.

DEAR ARTIST: You are not only artistic, but witty as well. Your creativity came in handy when the bloom was off the rose.

To receive a collection of Abby's most memorable -- and most frequently requested -- poems and essays, send a business-sized, self-addressed envelope, plus check or money order for $5 (U.S. funds) to: Dear Abby -- Keepers Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in the price.)

DEAR ABBY: After a two-year engagement, my husband and I were married three years ago. After the engagement announcement, my mother surprised me with the news that she and my father were going to renew their wedding vows. I was happy for them until my mother began planning their ceremony around the time of our wedding. I felt she was trying to steal the limelight from me -- and she did.

Two months ago, I announced that I am two months' pregnant. Yesterday, my mother announced that SHE is pregnant. (She had me when she was 15.) Abby, now she wants us to have baby showers on the same day. Do you think this is my mother's attempt to stay connected with me? -- TRYING TO REMAIN CALM IN DENVER

DEAR TRYING: No. I think that on an unconscious level, there is competition going on. However, since there is nothing you can do about it, the best advice I can offer is to live your own life, and spend less time looking over your shoulder to see what your mother is doing. Under no circumstances should you allow these "coincidences" to lessen your own happiness.

DEAR ABBY: I am a freshman at a college located two hours away from home. My brother, "Jeff," who is three years younger, still lives at home. I miss him until he comes to visit -- then it's a different story.

Jeff shows no respect for me, my lifestyle or my dorm room. He demands that I entertain him -- even though my schedule is filled to the max with classes and work. He makes a mess of my room (like spilling soda and not cleaning it up) and makes rude comments about my boyfriend behind his back. My brother has gone so far as to make some outrageous statements like, "Anyone who is not Christian is going to hell!" (My boyfriend is Jewish.)

How am I supposed to continue having Jeff visit if he causes nothing but stress and embarrassment and leaves my room trashed? My parents don't see any problem and think I'm blowing this out of proportion. Any suggestions, Abby? -- FED UP IN NEW YORK STATE

DEAR SIS: There may be only three years' difference in your ages, but emotionally your brother is a rebellious, self-centered adolescent.

If I were you, I would limit Jeff's visits until he's older, wiser, and willing to show more respect and tolerance for you and your friends.

DEAR ABBY: I am a mother of five who has been married for 18 years. The letters in your column from brides-to-be and graduates asking the best way to keep track of gifts prompts me to write.

When I was 20 and planning my wedding, my mother-in-law-to-be gave me a terrific tip: The name, address and phone number of each guest attending the wedding was written on a 3-by-5-inch index card and stored alphabetically in a recipe box.

After the wedding, as my husband and I opened each gift, we wrote what the gift was on that person's index card and returned it to the box.

When it was time to write thank-you notes, I needed only to refer to the box to know who gave what and never had to worry about a "lost" address or gift card. All the necessary info was right there on the cards -- and in alphabetical order. -- JUDY IN OHIO

DEAR JUDY: That's a wonderful idea, one that's easy to implement and can alleviate a lot of headaches. In this day and age, when the thank-you note responsibilities are shared by both brides and grooms, I'm sure your suggestion will be appreciated.

For everything you need to know about wedding planning, order "How to Have a Lovely Wedding." Send a business-size, self-addressed envelope, plus check or money order for $5 (U.S. funds only) to: Dear Abby, Wedding Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)