DEAR ABBY: I am 21 1/2 years old and was married when I was 20. I thought at the time I was doing the right thing, but now, after a year and a half of marriage, I realize it was a mistake. I was too young to get married.

My husband and I disagreed on too many things, so now we are getting a divorce. He doesn't want it, but he says if I pay for it, he will sign all the required papers. We have nothing to divide. No house, no car, no money and no kids. Nothing to fight over.

Now for my problem: I went to a legal clinic and they told me there wasn't any "no-fault divorce" in Cook County, Ill., which is where we live. This means I will have to go to court and claim "mental cruelty."

Abby, there was no mental cruelty, so why do I have to go to court and lie -- especially since my husband agreed to cooperate? Isn't there someplace that we could go and just sign some papers and be divorced? Why must I point a finger of blame at a perfectly nice man? The marriage was MY mistake.

Also, I would like to know why a divorce should cost so much? I was quoted a figure of $970. There is nothing to divide up, and my husband is not going to contest the divorce. Isn't there a cheaper and easier way? -- NOBODY'S FAULT

DEAR NOBODY'S FAULT: A cheaper divorce would be available through your legal aid society -- only if you are unemployed.

According to Dorothy B. Johnson, attorney at law and chairperson of the Chicago Bar Association Matrimonial Law Committee:

"Since July 1, 1984, there has been another ground for dissolution of marriage in Illinois, which you and your spouse may find more suitable: 'irreconcilable differences.'

"As for the cost of your divorce, the rate you were quoted is not out of line for the greater Chicago area."

DEAR ABBY: The letter from a woman who had witnessed a father abusing his young son in a department store, and she didn't know what to do or say, bothered me. You seemed to be sympathetic with the abuser and suggested that she could have said, "I know how you must feel -- shopping with children isn't easy," which would seem to give approval to the father's actions.

The other day, I witnessed a similar situation involving a young mother in a checkout line in a supermarket. Her child had obviously misbehaved and the mother was berating him with some harsh words that can hurt a child more than physical blows!

A woman in line in front of them turned around and delivered what I thought was the perfect remark: "I'll give you a dollar for him!"

That one sentence reminded the young mother of the value of her child.

I wish I had said it. -- SYLVIA E., LOS ANGELES

DEAR ABBY: I have never written to you before, but after reading about the old gentleman who is still making love often at the age of 85, I took the newspaper out of the trash can three times to make sure I had read it correctly.

I would sure like to hear his wife's side of this story. I'll bet she is sick to death of it. Or maybe she is like me, going through the motions and faking it.

I am a 65-year-old woman married to the most wonderful man in the world, and I have been faking it for years. How many letters have you gotten on this one? I would love to know. -- "B" IN DALLAS

DEAR "B": Thus far, only a few, but I would welcome letters or postcards (unsigned, of course) from other females who have been "faking it" for years.

"How to Be Popular" is an excellent guide to becoming a better conversationalist and a more attractive person. To order, send a long, business-size, 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. (Postage is included.)

DEAR ABBY: I am a child psychologist and the mother of two. There is certainly controversy in the field of child development concerning pacifiers. However, most professionals believe that there is no harm in giving pacifiers to infants as long as the pacifier is "orthodontically approved" -- meaning the shape prevents the development of a tongue-thrusting habit.

It is important to understand that the sucking reflex, being necessary for survival, is the strongest reflex in a newborn. Some infants display a stronger need to suck than others. If a mother were to attempt to satisfy this need with breast or bottle, the result would be overfeeding -- and a very tired mother.

Use of a pacifier is harmless as long as the infant is weaned from it, much as one weans a baby from a bottle.

My younger daughter was born with an extremely strong sucking reflex. When the pediatrician came to the hospital and lifted her from her bassinet, all of the bedding came with her -- she had tried to stuff it into her mouth! The pediatrician said, "I hope you have a pacifier at home."

Abby, the next time you print a letter from a "child development specialist," please check with other professionals before unnecessarily alarming thousands of parents who are already bombarded with well-intentioned advice from every side. As with everything, moderation is the key. -- PRO-PACIFIER, MONROE, MICH.

DEAR PRO-PACIFIER: Meet another pro-pacifier enthusiast who shares your opinion of the child development specialist.

DEAR ABBY: I am really incensed by this "child development specialist" who, by sheer ego and self-importance, purports to know more than the instincts of a mother.

I am equally incensed at her allegation that parents who give their children pacifiers are really pacifying themselves to keep their children quiet.

How dare this "child development specialist" insinuate that I am a bad mother for using pacifiers! If I were to listen to the constantly changing theories of these child development specialists and actually put to use some of their theories, my children would be so confused, they wouldn't know which way is up!

I would like to see the research that backs up her theory that the use of pacifiers can lead to smoking, overeating and alcoholism. Furthermore, what makes this woman a "child development specialist"? Is it education or experience? If experience counts for anything, I am a child development specialist myself. I'm raising twins. -- PAM ISAACSON, EL PASO

DEAR ABBY: Some very close friends are planning a surprise 25th wedding anniversary party for a special couple we all love.

The friends who are planning the party want all the other friends of this couple to participate. Would it be considered tacky to put on the invitation: "In lieu of a gift, please make a cash contribution to help defray the cost of catering"? -- "US" IN BALTIMORE

DEAR "US": Yes, it would be tacky. If the "very close friends" want to plan the party together and split the cost, fine -- but do not ask the invited guests to chip in.

What teen-agers need to know about sex, drugs, AIDS, and getting along with their peers and parents is now in Abby's updated, expanded booklet, "What Every Teen Should Know." To order, send a long, business-size, 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. (Postage is included.)

DEAR ABBY: In Richland, Wash., men and women are carrying signs and parading small children in front of family-planning clinics in opposition to a woman's right to choose.

Meanwhile, a newborn baby boy was dumped in an apartment complex trash bin and left to die. He was found, hospitalized and survived. The baby, his 17-year-old mother and another son, a 1 1/2-year-old, have been placed in separate King County foster-care families.

Abby, please print the letter signed "Hates Hypocrites" again. In light of the abovementioned incident -- which is occurring all over the nation -- that letter needs to be seen again. -- BARBARA HARROW, RICHLAND, WASH.

DEAR BARBARA: Indeed I will. And here it is:

DEAR ABBY: This is a message to those men and women who try to prevent women from entering abortion clinics and carry big signs that say, "They Kill Babies Here!"

Have you signed up to adopt a child? If not, why not? Is it because you don't want one, can't afford one, or don't have the time, patience or desire to raise a child?

What if a woman who was about to enter a family-planning clinic saw your sign, then decided not to have an abortion but chose instead to give her baby to you? Would you accept it? What if the mother belonged to a minority group -- or was addicted to drugs, or tested positive for AIDS?

Why are you spending your time carrying a sign? Why aren't you volunteering to baby-sit a child born to a single mother so she can work? Why haven't you opened your door to a pregnant teen-ager whose parents have kicked her out when she took your advice and decided not to have an abortion?

As for the taxpayers who resent paying for abortions, who do you think pays for foster care, welfare, social workers and juvenile delinquency? The taxpayers.

Let's talk about something money can't buy: love. Have you ever visited a home for abused and unwanted children? Have you ever been to juvenile hall and seen the children who have committed crimes because they were born to mothers who didn't want them?

I'm not thrilled about abortion, but I don't think anyone has the right to tell others not to have one unless he or she has done the things I have mentioned above.

So, to those carrying those signs and trying to prevent women from entering family planning clinics, heed my message: If you must be against abortion, don't be a hypocrite -- make your time and energy count. -- HATES HYPOCRITES IN SANTA ANA, CALIF.

DEAR HATES: I couldn't have said it better. Or as well.

DEAR ABBY: To the Caucasian couple with the adopted Korean child: I, too, have been confronted by many unthinking strangers with rude comments. My most memorable occurred while grocery shopping with my blond-haired, blue-eyed biological son and my dark-haired, dark-complexioned adopted daughter.

A woman approached me and asked, "Are these your children?"

"Yes," I answered.

"Different fathers?" she asked.

"Yes, and different mothers, too," I replied.

"Oh," she said, looking confused. "With people sleeping around so much these days, I just thought --" I didn't let her finish. I just walked away and left her with her big mouth hanging open. -- C.M. IN APPLE VALLEY, MINN.

Hot off the press -- Abby's new booklet, "The Anger in All of Us and How to Deal With It." To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Anger Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)