DEAR ABBY: I am a 38-year-old woman. When I was in my mid-20s, my doctors told me I could never have children. At that time I was dating "Doug" and told him about my infertility. He said it didn't matter to him.

We became engaged and I started planning the wedding. After all of the plans were made, Doug changed his mind about wanting to marry me. He said that after thinking it over, being a father was very important to him. I was devastated.

I have now been dating a very nice man for two years. He has told me that the fact I can't have children does not affect his feelings for me, and that if we decide we want a family we can always adopt. He says that he'll never let me go. But how can I believe him, Abby? -- CAN'T TRUST IN CAMBRIDGE, MASS.

DEAR CAN'T TRUST: Doug was a cad. However, just because you got a bad egg once doesn't mean you should give up on finding a man you can trust. Not all men are alike. The one you're dating now sounds like a keeper to me.

DEAR ABBY: My sister and her husband and children have completely severed their relationship with our brother because of his new wife's gift-giving practices.

On my teen-age niece's last two birthdays, our brother's wife has given her a "gift" of used clothing still reeking of our sister-in-law's perfume. My sister and her daughter were very hurt by these tacky gifts.

Our brother and his wife shop for themselves in thrift shops. They don't have to shop there, but they choose to. However, neither my sister's family nor myself is comfortable doing so.

Abby, I'm usually the family peacekeeper, but I'm open to any suggestions. Should I say something, or should I keep my mouth shut and let them resolve this? -- IN THE MIDDLE IN TUCSON

DEAR IN THE MIDDLE: It's unfair for your sister to cut your brother out of her life without explaining why. Encourage her to explain politely, but truthfully, why they have stopped speaking -- but after that, you should stay out of it.

DEAR ABBY: Recently, in the middle of the night, a friend had chest pains. She called a neighbor and was taken to the hospital, where she was treated. Fortunately, all is well. However, her doctor told her that what she had done was wrong. He said, "You should never call a friend or neighbor; they are not equipped to help you in an emergency. Call 911!"

She told me this story, and two weeks later, I was at a friend's for New Year's. I ate too much salty food and suddenly was gasping for breath. I had just told them the story about 911 that evening. They did just that -- called 911 -- and within minutes a police officer arrived with oxygen, administering it while waiting for the ambulance. I'm convinced it saved my life. -- RUTH DAIGEN, WANTAGH, N.Y.

DEAR RUTH: I'm sharing your story with my readers because it illustrates what 911 is supposed to be used for -- a life-threating emergency. Thank you for an important letter.

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 $3.95 ($4.50 in Canada) to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)

DEAR ABBY: Two months ago my youngest sister called me -- collect again -- sobbing that she felt alone and frightened in the world. She asked if we could meet for tea or if I could visit her. As a mother of twins and self-employed, I reminded her that having tea in a cafe is a luxury I cannot afford.

Last month she called me again. She wanted to spend Saturday night with us and make a pancake breakfast "for old times' sake." She told me she missed me and felt blue. (Abby, Saturday nights are reserved for my husband.)

Two weeks ago, my sister invited me to a matinee -- her treat. She tearfully informed me that she was not sleeping well (she was being treated for depression and chronic fatigue syndrome). I told her, "Working people don't go to matinees, but when you get your life together, you'll know what 'chronic-living-life-fatigue' is."

My little sister will never call again. She took her life last week.

My sister had some of the best medical help available, and I know she was ultimately responsible for her own life. But I also know that I'll never again brush her hair out of her sleepy blue eyes or trade my blouse for her mauve lipstick, or tell her she's not fat -- she's beautiful.

Most of all, I will never forgive myself for not realizing how suicidal my sister was. Perhaps this letter will prevent others from making the mistakes I made. -- LESSON LEARNED IN THE WORST OF WAYS

DEAR LESSON LEARNED: Please accept my sincere sympathy on the tragic loss of your sister. It is vital that you understand it's common for those who survive the suicide of a loved one to experience guilt, and to feel that somehow they could have prevented the tragedy.

True, agreeing to get together with your sister when she asked would have given you different memories, but in all likelihood, it would not have prevented her from taking her life. Her troubles were far deeper than a social visit could have remedied.

I urge you and anyone who is struggling to cope with the suicide of a loved one to find a support group. Any crisis center or suicide hotline can refer you to a group in your area.

Please write to me again. May God bless you -- and he will if you have faith.

DEAR ABBY: My best friend and I just returned from a week of hiking along the Washington coast. On our last night, we stayed at a fancy lodge to rest before returning home. My friend suggested that next year he bring his wife and we invite another couple to join us so we could rent a cabin overlooking the coast. Since I am single, that means five of us would be occupying the cabin.

My friend suggested we split the bill three ways. I said the bill should be split five ways. He became upset at my suggestion and hasn't spoken to me since we returned home.

Thinking I may have been out of line, I asked my family and close work associates how this bill should be split. My question has generated quite a debate, with only my brother and two co-workers agreeing with me. We are all waiting for your thoughts on how to split the bill -- and I will abide by your advice. -- ALAN IN MONTESANO, WASH.

DEAR ALAN: If you are on a tight budget, "take the fifth." Otherwise, assume one-third of the expense.

For an excellent guide to becoming a better conversationalist and a more attractive person, order "How to Be Popular." Send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby Popularity Booklet, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)

DEAR READERS: Can you believe it? It's Valentine's Day already! And what better time to revive my Ten Commandments of Love.

Yes, dear readers, I actually had the chutzpah to write my own Ten Commandments. But it wasn't as though I was stealing from strangers; one of my ancestors was privileged to have received them on Mount Sinai from the Lord himself -- at least that's what the Good Book says.

Originally, I wrote two sets of commandments -- one for men and one for women. Then Mandy Stillman, a lawyer from Milwaukee, pointed out that one set of commandments should apply to both men and women. She was right, of course. So how's this for a gender bender?

THE TEN COMMANDMENTS OF LOVE

-- Put your spouse before your mother, your father, your son and your daughter -- your mate is your lifelong companion.

-- Do not abuse your body with excessive food, tobacco, drink, or any foreign substance that goes into your arm or up your nose.

-- Remember that cleanliness is a virtue.

-- Willingly share all of your worldly goods with your mate.

-- Do not forget to say, "I love you." Even though your love may be constant, your spouse needs to hear those cherished words often.

-- Remember that the approval of your spouse is worth far more than the adoring glances of a hundred strangers, so be true to him or her, and forsake all others.

-- Permit neither your business nor your hobby to make you a stranger to your spouse. The most precious gift you can give is time.

-- Keep your home in good repair, because out of it come the joys of old age (not to mention its resale value).

-- Forgive with grace, because who among us does not need to be forgiven?

-- Honor the Lord your God every day of your life, and your children will grow up to bless you.

Today, be a sweetheart. Call someone you love and say, "I love you." (Make two or three calls; who says you can't love more than one person -- in different ways, of course.)

Go through your closets and give all those clothes that you've been saving until you lose 10 pounds to your favorite charity. Call someone who's lonely and say, "I'm thinking of yu." Or, better yet, say, "I'll be over tomorrow to take you to lunch, run some errands for you, or give you a ride."

Visit a sick friend. Say a prayer. Donate some blood. Adopt a pet. Will your eyes, your kidneys and all your usable organs to someone who can use them after you're gone. Forgive an enemy. Hug your teen-ager. Write a fan letter. Listen to a bore. Pay your doctor. Tell your parents you think they're wonderful. Spay your dog. Neuter your cat. Quit smoking. Drive carefully. If you're walking, watch where you're going.

And don't wait until next year to be a sweetheart again. -- LOVE, ABBY

DEAR ABBY: Like "Examining Life in Ohio," I also dreamed of a soul mate after a long so-so marriage in which neither of us was fulfilled. After my husband died, I adopted a "leave the door open a crack" attitude toward every man I met. He might not be handsome, articulate or well-dressed; he might be too short, too fat or bald, but underneath might lurk the man of my dreams. Well, I finally met him!

How did we know we were soul mates? Because we never stopped talking, could read each other's minds and were comfortable with each other from the day we met.

After five months we were married. He was 69 and I was 68. We've had seven glorious years together, we are still reading each other's minds, and neither of us can shut up! -- BARBARA MILLER, EL CERRITO, CALIF.

DEAR BARBARA: Lucky you, and may it ever be thus. Your experience reminds me of an old saying, "It may take some searching, but there's a lid for every pot."

(Everybody has a problem. What's yours? Get it off your chest by writing to Dear Abby, P.O. Box 69440, Los Angeles, Calif. 90069. For a personal reply, please enclose a stamped, self-addressed envelope.)