DEAR ABBY: My wife and I are very worried about the safety of our two toddlers -- a 3-year-old boy and a 15-month-old girl. Their twin 7-year-old cousins have no manners, discipline or consequences in their lives. They have recently begun seeing a psychiatrist because they have been found with knives, or making stabbing motions toward themselves screaming, "Kill me now!"

Every member of the family agrees they are out of control, but nobody does anything to correct their behavior. When we told my mother-in-law we didn't want our children around the twins without direct supervision, her response was she "couldn't watch them every minute." We said fine, we would bring the kids over and one of us would directly supervise them. This led to an uncomfortable silence that lasted a few days, until today when my wife took the kids to her parents' for a birthday party. The afternoon went by with the twins' usual defiance, rudeness and belittling of any adult in sight.

After she returned from my in-laws', my wife proceeded to tell me their bay window had a hole in it because one of the twins had shot a loaded gun through it. I am stunned that while we have been discussing the safety of our children, her parents have been leaving a loaded gun lying around. (Publish this for the world: If you need a gun to defend your bird feeder, especially when it's smack dab in the middle of two houses -- get rid of the bird feeder.) My wife said her father yelled at the twins, although he had left his loaded gun in plain sight.

How can I make it clear to my in-laws that they must step up their level of supervision, and that my sister-in-law's kids are headed for serious trouble? -- WORRIED DAD IN VERMONT

DEAR WORRIED DAD: To paraphrase an old saying, there are none so blind as they who will not see -- so stop trying to "reason" with them. To leave a loaded gun lying around with children in the house is reckless endangerment. Because it should be clear to both you and your wife by now that your children are not safe at her parents' house, visits with their grandparents should be at your house or on neutral turf. And their time with their cousins should be limited and strictly supervised, if permitted at all.

DEAR ABBY: I was married to an impotent doctor in New York for three years. He told me I was the cause of his problem -- that I was too fat (I weighed 115 pounds), and that he wasn't attracted to me. As time passed, I realized that he was being cruel to me to deflect attention away from his real problem, his impotence.

Finally, on the day he got his green card (I sponsored him), he left me, so I had the marriage annulled. I stayed with him despite his problems because I thought that is what a devoted wife should do. I had no idea he had been using me all along to establish his career in the U.S.

Have you any advice for getting past this? Most women in their 20s have never had to deal with such a problem, so it's difficult to discuss with family and friends. -- TAKEN FOR A RIDE IN NEW YORK

DEAR TAKEN FOR A RIDE: You were, indeed, taken advantage of and you have my sympathy. Instead of a healer, you married a heel. Please don't jump to conclusions. I'm sure there are many victims of fraud in their 20s -- and you may qualify for counseling through your state's victim/witness program. Your local police department should have information about it, and I believe you would qualify.

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 $10 (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 just read your response to "Nameless in a Red State," who asked if she could become addicted to drugs by having sex with an addict.

You were correct to point out that it's important she stay away from people who are addicted to drugs if she wants to stay clean. I work in a methadone clinic. My clients know they have to be careful who their friends are. It is very easy to start using drugs again while in treatment if you're spending time around people who are using.

I was, however, disappointed that you didn't mention that having sex with a drug addict is a recipe for getting AIDS and many other sexually transmitted diseases. (I call it the gift that keeps on giving.) People must remember that when they have unprotected sex with someone, they are also having sex with everyone that person has had sex with. Latex condoms are the best defense against sexually transmitted diseases. -- R.N. IN BLUE NEW JERSEY

DEAR R.N.: I'm sorry you were disappointed that my answer didn't go far enough; however, the woman's question was, "Can I become addicted to drugs by having sex with an addict?" I answered her question factually and specifically.

I also heard from a physician who felt I should have elaborated further. Read on:

DEAR ABBY: In your reply to the writer, you failed to mention the most dangerous complications of such behavior, infection with potentially fatal diseases such as hepatitis B, hepatitis C or AIDS. There is a high incidence of these diseases among drug addicts because of the sharing of contaminated needles, and they can also be transmitted through sexual relations. -- ALEXANDER N. ZINN, M.D., WINNETKA, CALIF.

DEAR DR. ZINN: Your letter makes me wonder how many lives could be saved if clean-needle exchange programs were available in every city. Thank you for clarifying my answer.

DEAR ABBY: We had a houseguest recently who asked to use my computer to check on his airline flights. After he left, I went into the history to check out a previous site I had used and found my computer full of adult porn sites. These sites were surrounded by his airline reservations, so it could not have been anyone else using my computer.

I erased the sites and then cleared out the cookies, but now I'm getting reports from friends that they are getting adult porn pop-ups when I send an attachment. I will contact my Internet service provider, but I will probably need to get a new e-mail address.

My husband and I are not sure how to handle this. Should we tell him we know what he did on my computer, or do we just avoid him when he makes contact with us again? If I never see this person again it won't be a hardship. I feel violated. Any suggestions? -- PIQUED IN PALO ALTO

DEAR PIQUED: Your houseguest should be made aware of the problems his little surfing adventure have caused you. If it were me, I'd pick up the phone and give him holy heck for taking advantage of my hospitality in that way. If you want to avoid him in the future, it's certainly your privilege, but he owes you an apology, and you should collect it.

To receive a collection of Abby's most memorable -- and most frequently requested -- poems and essays, send a business-sized, self-addressed envelope, plus check or money order for $5 (U.S. funds) to: Dear Abby -- Keepers Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in the price.)

DEAR ABBY: My ex-husband, "Greg," is being married in the fall to a wonderful woman I have come to regard as a friend. "Marla" is good to my two little boys. She pays their child support on time, attends every one of their school functions and sporting events, and loves them like they're her own.

I'm wondering if I should try to convince Marla not to marry Greg because he is very abusive. He has had problems with the law and was extremely violent during our marriage. I have the pictures to prove it. He even beat up my mother one time.

Members of Greg's family have told me he's already showing signs of being abusive to Marla. Should I voice my fears to her, or just be thankful there's someone there that I can trust with my boys? -- TROUBLED IN NEW JERSEY

DEAR TROUBLED: Listen to your conscience and tell her what she could be in for. Don't be heavy-handed about it. Just arrange a private get-together and tell her you would hate to see what happened to you happen to her. Then take out the pictures and show them to her. If the spousal abuse is mentioned in your divorce papers, share that with her, too. After that, the decision is hers.

CONFIDENTIAL TO MY READERS: If you're looking for the "purrr-fect" gift for the cat lover in your life, I have the item. It's a fascinating, beautifully illustrated history of human-feline relationships, starting with cats' exalted status among the ancients as royal or sacred beings. The author is pioneer foreign correspondent, expert in international affairs and passionate cat-lover Georgie Anne Geyer, who traveled through the Middle and Far East to research the origins and characteristics of the 41 recognized modern cat breeds. The title is "When Cats Reigned Like Kings" (Andrews McMeel Publishing, $24.95). Available in bookstores, it's truly an "a-meow-sing" read!

CONFIDENTIAL TO MY READERS: If you're looking for the "purrr-fect" gift for the cat lover in your life, I have the item. It's a fascinating, beautifully illustrated history of human-feline relationships, starting with cats' exalted status among the ancients as royal or sacred beings. The author is pioneer foreign correspondent, expert in international affairs and passionate cat-lover Georgie Anne Geyer, who traveled through the Middle and Far East to research the origins and characteristics of the 41 recognized modern cat breeds. The title is "When Cats Reigned Like Kings" (Andrews McMeel Publishing, $24.95). Available in bookstores, it's truly an "a-meow-sing" read!

Good advice for everyone -- teens to seniors -- is in "The Anger in All of Us and How to Deal With It." To order, send a business-size, self-addressed envelope, plus check or money order for $5 (U.S. funds only) to: Dear Abby, Anger Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)