DEAR ABBY: I am 27, and my wife, "Marybeth," is 26. We recently went to my folks' house for supper. That evening a heavy snowstorm was starting and, because the trip home is 30 miles, we decided to stay overnight.

My old bedroom is upstairs, as are the rooms of my brothers, ages 25, 24 and 22. The guest room is downstairs. Because the room is quite small, and Marybeth said she felt a cold coming on, we decided I'd sleep in my old room.

The next day, while we were driving home, Marybeth told me she was glad I had come to her room after all and made love to her.

Abby, it wasn't me! She had mistaken one of my brothers for me in the darkness. We are all about the same size and build.

I have talked to each of my brothers (they all know about this), but they won't say who it was for fear of causing a rift between the guilty party and me. I told them that unless I find out who it was, there will be a permanent rift between all of us. (Marybeth still doesn't know it wasn't me.)

How do I handle this? -- ENRAGED IN ROCHESTER, N.Y.

DEAR ENRAGED: While you and your brothers may have a strong family resemblance, I find it hard to believe that you all smell, taste and make love like clones. So please do not accept as gospel that your wife didn't have an inkling that it wasn't you. As to who actually crept into her bed in your absence, if your brothers won't reveal who the guilty party is, then they're all equally guilty, and I wouldn't blame you for severing ties with them.

It's time to have a serious chat with your wife and get chapter and verse on what happened that night. Then she should be tested for STDs and treated if necessary.

It is possible for a couple to get past something like this, if you're both willing to work at it. The shortest route would be with the help of a licensed family therapist.

DEAR ABBY: I'm 19 and have a 9-month-old, "Sean." I live with his dad, "Richie," and my father-in-law, "Dick."

Dick drinks a lot and offers my baby beer. Dick also likes to tease Sean. He also leaves coins, toothpicks and cotton swabs on the floor, where Sean sometimes sleeps.

My son puts everything he can put his hands on into his mouth. Dick loafs all day and doesn't pay any of the bills. Please give me some advice. I'm so stressed out, I don't know what to do. -- STRESSED OUT, MIDLAND, TEXAS

DEAR STRESSED OUT: First, your baby should not be sleeping on the floor in these conditions. Second, offer your husband a choice. Either he insists that Dick straighten up his act, or you'll take Sean and make other living arrangements.

It's important, for your son's sake, that you draw the line NOW -- even if it means getting a job and putting your baby in day care. For "Grandpa" to give him alcohol is against the law. And if you don't put a stop to it, it could be considered child endangerment.

CONFIDENTIAL TO MY IRISH READERS: A Happy St. Patrick's Day to you all.

"May the road rise to meet you,

"May the wind be always at your back,

"May the sun shine warm upon your face,

"May the rain fall soft upon your fields,

"And, until we meet again,

"May God hold you in the palm of his hand."

Abby shares more than 100 of her favorite recipes in two booklets: "Abby's Favorite Recipes" and "More Favorite Recipes by Dear Abby." Send a business-size, self-addressed envelope, plus check or money order for $12 (U.S. funds)

to: Dear Abby -- Cookbooklet Set, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in price.)

DEAR ABBY: I'm married to a wonderful man. "Dave" and I are in our late 30s.

When Dave was about 5, he was with two of his cousins who were about the same age. The three were inseparable. While they were playing, the smaller cousin fell into a pond, and the older one jumped in after him and tried to save him. All my husband could do was stand and watch as both of his little cousins -- his best friends -- drowned before his eyes. He ran for help, but by then it was too late.

I know most of the story from my mother-in-law, as Dave is unwilling to talk about it.

Last night, I went upstairs and there was my darling, weeping uncontrollably. Dave told me that he lives with horrible depression every day because of what happened, and he can't get past it. I want my husband to see a grief counselor, but he refuses because he doesn't think he'd be able to talk about it.

Abby, I love my husband. He doesn't deserve to live with this horror for the rest of his life. How can I convince him to get professional help? -- HURTING FOR MY HUSBAND

DEAR HURTING: Remind Dave that when this happened, he was only 5, and under the circumstances, he did everything he could to save his cousins. Although this incident, which has haunted him all these years, will be difficult to talk about, it's the only way to rid himself of the feelings of helplessness and survivor guilt from which he is clearly suffering.

Talking to a counselor will help him to reclaim his life and rid himself of his depression. For a couple of sessions, he may indeed just sit there and cry. But tears can be healing. And eventually he WILL be able to talk about what happened.

Clip this column, give it to your husband, and tell him that I, too, am urging him to get the help he needs. He's in my thoughts and prayers, and the longest journey begins with a single step.

DEAR ABBY: I was recently at a family gathering with my husband's family. His uncle was hosting the party, and his wife asked me a question that I honestly didn't know the answer to.

His uncle's wife asked me how she should introduce me to their friends. Should she say, "This is our nephew's wife" or should she introduce me as their "niece"? What's the right answer for a situation like this? -- NANCY IN ARNOLD, MD.

DEAR NANCY: Tell your husband's aunt that the next time she makes the introductions, she should say, "This is our nephew, 'Bob,' and his lovely wife, Nancy," and to say it with a smile.

For an excellent guide to becoming a better conversationalist and a more attractive person, order "How to Be Popular." Send a business-size, self-addressed envelope, plus check or money order for $6 (U.S. funds only) to: Dear Abby Popularity Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: I recently turned 40, and because I don't get along with my husband "Ted's" family, I chose to celebrate out of town with my parents and siblings. At the end of my five-day trip, Ted picked me up at the airport and barely greeted me. He waited three days to give me my birthday gift.

When he finally handed me the box, Ted didn't even wait for me to open it. He went off to take a shower. I waited for him to finish, then opened the gift in front of him. Inside was a pair of diamond earrings.

I have never wanted diamond earrings, and I have told him so many times. I had asked Ted for cash so I could buy a new sewing machine. Why diamond earrings?

That night we had a major quarrel, and now I'll never be able to enjoy them. What do I do with them now? -- TICKED OFF IN RHODE ISLAND

DEAR TICKED OFF: First, you apologize for being ungracious about the gift your husband gave you for your birthday. Then sit down and try to analyze why you and his family don't get along and why your marriage is in serious trouble -- because it is.

After that, ask your doctor to refer you to a licensed marriage counselor and try to bridge the communication gap that has developed between you and your spouse. At this point, what to do with the diamond earrings is the least of your worries.

DEAR ABBY: I'm a 17-year-old high school senior. I got my driver's license around the same time as all my friends -- with the exception of my best friend, "Robin." Robin lives about 20 miles from my house, and anywhere I go she's always asking for rides. The problem is that I pay for my own gas and car insurance, and I only have a part-time job, along with baby-sitting.

Robin's mom told me she planned on giving me some gas money, but she only gave me $5. How can I keep from alienating my friend when I tell her I can't afford to keep going out of my way to get her unless she contributes more? -- BROKE IN NEW YORK

DEAR BROKE: A picture is worth a thousand words. Because you feel Robin may be too sensitive to be told in plain English, prepare a chart for her illustrating the distance from your house to hers and back, the mileage you get per gallon and the ever-increasing cost of gas. Illustrating the problem may help your friend see that what you're telling her isn't a personal rejection but a reality.

DEAR ABBY: I have an etiquette question. If you aren't supposed to wear white after Labor Day, when can you begin wearing white again? -- DEBBIE IN JONESBORO, ARK.

DEAR DEBBIE: You can wear white whenever the spirit moves you. According to "Emily Post's Etiquette," 17th Edition: "The old rule about wearing white only between Memorial Day and Labor Day is a thing of the past. Today the question of wearing white applies to the WEIGHT of the fabrics, not COLOR. (Italics are mine.)

"Lightweight fabrics in white and pastels are worn in the warm/hot months and heavier fabrics known as 'winter whites' are worn in the cool and cold months. Since the country includes varied climate zones, the times for switching between summer and winter whites will depend on the weather where you are."

What teens need to know about sex, drugs, AIDS and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $6 (U.S. funds) to: Dear Abby -- Teen Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in the price.)