DEAR ABBY: I've been writing this letter off and on for two years - and I'm finally sending it. Many times I've read about women who have been left to raise their children alone. What about men whose wives have deserted them? I'm the third one I know of in my town. Is this a new trend?

My wife left me with four children to raise. I would like to have companionship, but when a woman hears that I have four children, she says, "FOUR children - you must pay a lot of child support!"I say, "No, I have custody." Then she says, "That's too much for me to handle. Goodbye."

Abby, I love my children, and if it means giving them up in order to date, I'll stay single. I wonder how many other men out there are in the same boat? - FULL-TIME FATHER IN COLUMBUS, OHIO

DEAR FATHER: Have you never heard of Parents Without Partners? There must be some single mothers in your area who wouldn't mind joining forces with you.

To locate the PWP group nearest you, send a long, stamped, self-addressed envelope to: Parents Without Partners, 8807 Colesville Road, Silver Spring, Md. 20910.

Then get a sitter and go to those PWP meetings. You sound like a high-quality man. Don't be discouraged. A woman who would count you out because you have children probably would have been a poor mother for your motherless quartet. Keep looking.

DEAR ABBY: My husband and I have been married and on our own for seven years. We have two children. My husband has a large family - lots of aunts, uncles and cousins.

We were just invited to the wedding of one of his cousins. We didn't actually receive an invitation - on the invitation his parents received was a handwritten message: "Please ask Gary and his wife to come along, too."

I think it's a tacky way to invite people to a wedding. If they can't take the time and effort to find out what our address is (all they would have to do is ask Gary's mother), I really don't feel like going. My husband wants to go.

Maybe if you print this, they'll see it and realize how out of line they are. And just in case they don't see it, please tell me how to handle such invitations. - SECONDHAND INVITATION

DEAR SECONDHAND: This is indeed a tacky invitation. Either these people are trying to save the price of an invitation and/or the postage, or they just don't know better. Write them a note of thanks for the invitation, and add, "By the way, we have a home of our own now" and include your address and both your names.

DEAR ABBY: There is a fire hazard your readers should be aware of. If you have a paperweight or figurine positioned where direct sunlight can strike it - move it.

The glass paperweight on my desk was blistering the wooden finish in three spots when I noticed the streaks of smoke a foot high! I am just thankful that I was home and saw it before more damage was done. - WANDA IN ROCK STREAM, N.Y.

DEAR WANDA: Thanks for an important item. I called this seemingly improbable fire hazard to the attention of my readers several years ago, but it's worth mentioning again.

The facts about drugs, AIDS, and how to prevent unwanted pregnancy are all in Abby's new, expanded booklet, "What Every Teen Should Know." To order, send your name and address, plus check or money order for $3.50 ($4 in Canada) to: Dear Abby's Teen Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)