DEAR ABBY: I am desperate, so I will tell you my problem from the beginning. I am a 35-year-old mother of three. I divorced my husband twice for the same reason. Both times I caught him with another woman. (The same woman, and she was my best friend.)

Now I have a guy I think the world of. I love him like I have never loved anybody in my entire life. I can't stand being away from him. We have everything in common. He keeps telling me how much he loves me, and I know he isn't lying. He treats me like a queen. There is only one problem. He's living with another woman. He says he doesn't love her, and I believe him. He's too kind and decent to tell her he's in love with another woman. He says if she knew, she might even kill herself.

He doesn't want me dating anyone else, but he goes home to her every night and I'm alone.

I'm tired of hiding, but I'm afraid if I force him to make a choice, it won't be me. What should I do? -- A WOMAN IN LOVE

DEAR WOMAN: Brace yourself for some unpleasant news. The guy you are in love with has already made his choice, and it's not you.

Quit being available whenever he wants you. And quit hiding. The man is living with another woman, and he's cheating on HER to be with you. Please wise up and smell the skunk cabbage. This man is not worthy of your love.

DEAR ABBY: Tonight, while shopping at a large department store, I witnessed a man pull his son's hair and then he kept punching him very hard on his back and shoulders in an effort to make the boy obey.

The boy looked to be about 7 or 8 years old. The poor kid sat on the floor and cried silently while his father delivered these cruel blows with hate in his eyes. I stood no more than 3 feet away throughout this episode, searching for the right words to demand that he stop hurting the boy, but I feared that if I said anything, the man would be angered and embarrassed and would take his anger out on the child later at home.

Please address this issue, Abby. Tell your readers how to handle such situations. -- FEELING GUILTY FOR MY SILENCE

DEAR FEELING GUILTY: The scene you witnessed involved a man out of control. You could have very gently and quietly attempted to calm the father by saying, "I know exactly how you feel. Sometimes taking a child that age shopping is more than we can handle." And without being judgmental, in a soft and sympathetic tone, you would have intervened and brought an out-of-control man back to reality.

This sometimes takes more courage than most people have in today's "mind-your-own-business" society, but to do nothing while witnessing child abuse is indefensible.

Readers: There is now a toll-free National Child Abuse Hotline for adults to call when they feel that they are losing control. Dial 1-800-422-4453.

Most teen-agers do not know the facts about drugs, AIDS and how to prevent unwanted pregnancy. It's all in Abby's updated, expanded booklet, "What Every Teen Should Know." To order, send a 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: I am desperate, so I will tell you my problem from the beginning. I am a 35-year-old mother of three. I divorced my husband twice for the same reason. Both times I caught him with another woman. (The same woman, and she was my best friend.)

Now I have a guy I think the world of. I love him like I have never loved anybody in my entire life. I can't stand being away from him. We have everything in common. He keeps telling me how much he loves me, and I know he isn't lying. He treats me like a queen. There is only one problem. He's living with another woman. He says he doesn't love her, and I believe him. He's too kind and decent to tell her he's in love with another woman. He says if she knew, she might even kill herself.

He doesn't want me dating anyone else, but he goes home to her every night and I'm alone.

I'm tired of hiding, but I'm afraid if I force him to make a choice, it won't be me. What should I do? -- A WOMAN IN LOVE

DEAR WOMAN: Brace yourself for some unpleasant news. The guy you are in love with has already made his choice, and it's not you.

Quit being available whenever he wants you. And quit hiding. The man is living with another woman, and he's cheating on HER to be with you. Please wise up and smell the skunk cabbage. This man is not worthy of your love.

DEAR ABBY: Tonight, while shopping at a large department store, I witnessed a man pull his son's hair and then he kept punching him very hard on his back and shoulders in an effort to make the boy obey.

The boy looked to be about 7 or 8 years old. The poor kid sat on the floor and cried silently while his father delivered these cruel blows with hate in his eyes. I stood no more than 3 feet away throughout this episode, searching for the right words to demand that he stop hurting the boy, but I feared that if I said anything, the man would be angered and embarrassed and would take his anger out on the child later at home.

Please address this issue, Abby. Tell your readers how to handle such situations. -- FEELING GUILTY FOR MY SILENCE

DEAR FEELING GUILTY: The scene you witnessed involved a man out of control. You could have very gently and quietly attempted to calm the father by saying, "I know exactly how you feel. Sometimes taking a child that age shopping is more than we can handle." And without being judgmental, in a soft and sympathetic tone, you would have intervened and brought an out-of-control man back to reality.

This sometimes takes more courage than most people have in today's "mind-your-own-business" society, but to do nothing while witnessing child abuse is indefensible.

Readers: There is now a toll-free National Child Abuse Hotline for adults to call when they feel that they are losing control. Dial 1-800-422-4453.

Most teen-agers do not know the facts about drugs, AIDS and how to prevent unwanted pregnancy. It's all in Abby's updated, expanded booklet, "What Every Teen Should Know." To order, send a 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: I have been going with the same man for three years, and we are talking about marriage in the future. My only problem is that he wants to marry me only if he has a million dollars in the bank.

I met him like he is, and I truly love him for himself, but all he cares about is money, money, money!

Abby, is he giving me excuses? Or does he really want to give me a better life than the one we share now?

I wish I could read his mind and his heart. -- DETROIT NEWS READER

DEAR READER: Never mind his mind and his heart. Ask to read his bank statement to find out how close to a million dollars he is. If he's almost there, then I would say he has good intentions, but if he's in the neighborhood of $985,000 short, he's making excuses.

DEAR ABBY: "Lisa" and I have been best friends since high school. We even liked the same guy for a while. (I'll call him Bill.) Eventually, Lisa married Bill and I married someone else. I didn't see Lisa for several years, then one night I ran into Bill and he told me that their marriage was over, but Lisa wouldn't get a divorce because of how it would look to her family.

Not long after that, Bill and I had a one-night stand. We both felt so guilty, it never happened again. Then three months later, I saw the two of them together, and Bill couldn't look me in the eye.

Meanwhile, Lisa and I have become very close friends again, and every time we get on the subject of married people who cheat on each other, I want to tell her about Bill. I know if I tell her, I will lose her as a friend, but on the other hand, I wonder if I am being a good friend by not telling her. I'm willing to tell her, if she would just ask. Sometimes when we talk, I say something like, "I'd want to know if MY husband was cheating on ME," hoping she'll say, "So would I," but so far she hasn't.

I don't know what to do. I probably should tell her before someone else does. -- LAURA'S FRIEND

DEAR "FRIEND": With friends like you, Lisa doesn't need any enemies. Are you sure you wouldn't like Lisa to end her marriage so you could have Bill? Please do Lisa, Bill and yourself a favor and don't tell Lisa (or anyone else) about your one-night stand with Bill.

DEAR ABBY: When you get an invitation to a wedding and you can't go, are you obligated to tell them why?

I received an invitation to a church wedding that is scheduled for 10:30 in the morning. It's a good four-hour drive from where I live, and that's too long a drive and it's too early.

Also, if you get money from relatives as a gift, are you supposed to tell them what you bought, or did, with the money? -- PERPLEXED IN TUCSON

DEAR PERPLEXED: It is not necessary to state why you are unable to accept an invitation to a wedding -- or to any other affair -- but it softens the turndown if you can truthfully say that you are unable to attend due to a previous commitment or that you will not be in town.

When you receive a gift of money, you are not obligated to disclose how the money was used.

By popular request, Abby shares more of her favorite prize-winning, easy-to-prepare recipes. To order, send a long, business size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: More Favorite Recipes by Dear Abby, P.O. Box 17, Mount Morris, Ill. 61054. (Postage is included.)