DEAR ABBY: Seventeen years ago, I had a (minor) tryst with my wife's sister. Months later, it came to light during an unfortunate phone conversation. Since then, my wife and I have gone through years of counseling.

Our family has recovered and all is well -- except with my wife's brother-in-law (the husband). He considers me "persona non grata," and I have been excluded from all family functions, at least those he is involved in.

I took my counselor's advice and sent him a written apology, delivered by my wife. My parents-in-law have forgiven me (as well as their daughter) for the errant behavior, but still a massive wedge remains in our family. My father-in-law is ailing now and is desperate for reconciliation. I've done what I can (I think). What now? What more? -- PERSONA NON GRATA IN ILLINOIS

DEAR P.N.G.: You have already apologized. You can't force your brother-in-law to accept it. Because your father-in-law is desperate for reconciliation, he is the one who should appeal to your brother-in-law to heal the breach.

DEAR ABBY: In a world so vast and beautiful, do you think one person could somehow see it all? I've often dreamed of doing so, but most of the time I sit in front of a computer doing schoolwork. So many days I have wanted to drop out and be a hippie or something, but in these times, there are so many requirements to get to where we want to be and have what we've always wanted or needed.

You know what, Abby? I've got a better question for you. Can you invent a time machine so I can go back to the '50s? Forever wondering ... -- GABRIELLA IN SOUTH CAROLINA

DEAR GABRIELLA: I wish I could provide one, but if I did, I have a hunch it would become very crowded. Your yearning for the '50s may be happening because life in the 21st century has become stressful. It isn't just you -- for many people, the cycle of life seems to spin increasingly faster.

There's nothing wrong with dreaming about visiting faraway places. Once your studies are completed, you may be in a position to do that. In the meantime, make an effort to block out time to go to a gym, do yoga, meditate. If that's not possible, break up your routine with some other form of exercise. I can tell you from experience, it works.

DEAR ABBY: My wife and I have a 15-year-old daughter who has a boyfriend her age. Her boyfriend visits our daughter in her bedroom, where they lock themselves in for hours. I object to them being alone in a bedroom, but my wife says she "knows" her daughter and that there's nothing to worry about. Who is right? -- UNCOMFORTABLE IN THE SOUTH

DEAR UNCOMFORTABLE: YOU are! Your wife is dreaming! Tell your daughter that from now on, her door will remain open when anyone of the opposite sex is in there with her, or the lock will be removed. (Even better -- restrict their visits to the living room.) Do it now. Time may be of the essence.

TO MY READERS: A very merry Christmas to you all!

DEAR ABBY: I am a 56-year-old woman who has been with my boyfriend for seven years. He never lets me come to his place, but he comes to mine and stays every weekend.

He always has his married children staying with him, even though they are financially well off and don't need to. Every time I suggest we should be together by now, another child's family needs to move in, even stepchildren of his.

I left him for six months because I was tired of the rejection. We are back together again, and this last son and daughter-in-law (with their child and another one on the way) are there. Now he's saying he wants to move in with me because they need the room for the new baby. He says that's not the entire reason -- it's because he loves me -- but I suspect he doesn't want to be there with an infant on the way. I feel I'm being used, and I am not sure what to do. Advice, Abby? -- CROWDED HOUSE IN MICHIGAN

DEAR CROWDED HOUSE: Your boyfriend of seven years has made plain where his priorities lie. You have never been high on the list. In fact, you appear to have been more a convenience than a love interest.

The surest way to avoid being used is not to allow it. Do not permit him to move in unless you are clear on what your objectives are, and have a firm commitment or he will break your heart (again).

DEAR ABBY: I thought you might like a variation on one of your "Pennies From Heaven" stories. When I was in my early teens, I had a close friend whose grandparents picked us up every day from school. We would stay at their house for a few hours until our parents could pick us up.

One day as we were leaving school, her parents' car was there instead of her grandparents' and her mom broke the news that her grandfather had died that morning. Needless to say, we were both very sad.

The following day was partly cloudy and rainy. After school, we walked toward where we usually met her grandparents and we saw a rainbow. When my friend saw it, she looked at me and said, "He's OK!" She meant her grandfather. Ever since, when I see rainbows I think of him, even though that was almost 20 years ago.

Last month I was driving home on the same kind of rainy day, and when the sun peeked out from behind the clouds, I saw another rainbow. Of course, I thought of my friend's grandfather. Later that night I learned her grandmother had passed away that morning. When I told my friend about it, it made her cry. We both believe it was a sign from them that they are fine and together in heaven. -- RAINBOWS IN CALIFORNIA

DEAR RAINBOWS: Many readers have written to tell me they have found similar comfort after discovering coins that had emotional significance. If rainbows have special meaning for you, then I hope you will continue to enjoy them. Your letter made me smile. Thanks for sharing.

DEAR ABBY: I'm 18 years old and I have a son who's 3. I'm still in school and live with my parents.

My parents treat me like I'm a nobody and always bring up how I got pregnant. They barely allow me to take my son anywhere. I still have to ask them if I can go to certain places.

My dad takes it out on me when someone makes him mad. I'm always getting yelled at for everything, even if I did nothing wrong. My dad sees me as a failure even when I do something good for me and my son. Because I have a kid, he's never proud of me. I don't know what to do or how to make this better. -- OLD ENOUGH IN THE SOUTH

DEAR OLD ENOUGH: Your parents are still punishing you for having the baby. I'm glad you stayed in school, because the more education you can attain, the better able you will be to support yourself and your child.

It is important for your future that you quit looking to your father for approval. He's wrong to take his frustrations out on you. You may have disappointed him, but you are not a failure. If there are other relatives with whom you and your child can live while you complete your education, please look into it.

DEAR ABBY: So often we learn from your column what a good marriage is not -- how not to treat someone we love. Could you please describe for my granddaughter just what a strong, loving marriage is? Paint a picture of what to look for in a husband and how to create a marriage that will last while bringing joy to both parties. Your experience can help me explain this to her. -- PONDERING STILL IN HONOLULU

DEAR PONDERING: I can try. But before I do, I should mention that a good marriage may mean different things to different couples. To me, a good marriage is a solid partnership between two people who respect each other, care about each other and are mutually attracted. It helps if both have similar goals and values, and are willing to support each other in good times and in bad. Like anything that's worthwhile, marriage takes work, patience and willingness to compromise. And of course, communication -- which includes listening -- is key.

DEAR ABBY: I have a workplace challenge that requires your expertise. Our company sends greeting cards for every event that you can imagine. It's an effective way to show the employees that we are a team and care about each other. The problem is, one staff member has a habit of writing a "manuscript" (heavy sarcasm) on the inside of every card, whether or not she personally knows the individual. This leaves little space for anyone else.

I have jokingly asked the young lady to please be conscious of space, but she doesn't get it. I don't want to hurt her feelings, but people here are getting fed up. Would it be rude to take the card to her only after everyone else has signed it? -- PLEASE SIGN HERE

DEAR PLEASE: Rude? Not at all. It's a practical solution. Bravo!