Dear Annie: My husband and I are in our 40s. We have been married for 15 years and had a marriage most people would envy. We have no children.

My husband recently admitted to an indiscretion with a woman he has known for four years. This is not a woman he would ever take out in public. His pursuit of her was purely for sex. Once it happened, he never saw her again. (She confirmed this.) He only confessed because he developed a medical problem and was scared.

We are now separated and he is seeking counselling for self-esteem issues. He has begged and pleaded with me not to divorce him, but I feel as though I am married to a complete stranger. How could an intelligent, educated man who supposedly loves his wife actually go through with such an unspeakable act? Is it true "once a cheater, always a cheater"? Is there an explanation (other than midlife crisis) to assure me this was just a one-time experiment? – Heartbroken in the South

Dear Heartbroken: We don't know why your husband felt the need to cheat, although therapy should help him find out. And we can't promise he won't do it again, but if therapy helps him, there is a possibility this was a one-time deal. The issue, as always, is trust. Which is why we recommend counselling for you, too. Marriage doesn't come with guarantees. Counselling will help you decide if you can live with the uncertainty. You have to do what lets you sleep at night.

Dear Annie: My dad is a long-time survivor of Hodgkin's disease, but his battle has become a losing one and the doctors say he is terminal.

This wonderful man has always been the strength in my life. I would not be who I am today without him. I am heartbroken by what he has gone through this past year. I want him to get something like a last wish sort of thing, like they do for sick children. Is there something out there to grant wishes for adults who deserve that, too? My dad is very special, and I would love to remember him with a big smile on his face. – Daddy's Little Girl

Dear Daddy's Little Girl: While most such organisations deal with sick children, there are a few for adults, although they are not as expansive in scope as the more well-known groups.

Try Dream Foundation (dreamfoundation.com), 1528 Chapala Street, Suite 304, Santa Barbara, California 93101; Fairygodmother Foundation (fairygodmother.org), 213 West Institute Place, Suite 509, Chicago, Illinois 60610; The Dream Lives On (thedreamliveson.org), The Dave Bruchhauser Fund, 9138 Arlon Street, Suite A3 – Box 134, Anchorage, Alaska 99507 and Happiness Unlimited.

Dear Annie: I read the letter from "Perplexed in the Midwest'', who can't afford a diamond ring and asked if it was OK to get his girlfriend cubic zirconia.

My beloved husband was an expert in diamond cutting. When we were about to be married, he told me he was crafting my rings himself and had selected cubic zirconia instead of diamonds because of their astounding beauty and sparkle.

I was delighted, and all my friends were amazed at the size and fire of those brilliant stones. The local jeweller said they were "very difficult to discern" from diamonds costing thousands more.

To this day, cubic zirconia, which is not "cheap" – just inexpensive and sensible – is my own choice over diamonds. – Ben Dare Dun Dat

Dear Ben Dare: The value of the stone is only one factor in the selection of a ring. But it is important that the recipient not be tricked into thinking it's something other than what it is.