Q. This is going to be a new one, even for you. My wife's ex-husband, has invited us "for tea."

You have to understand that theirs was not a friendly divorce. As a matter of fact, he sued for adultery after having put detectives on us. We have not spoken in eight years.

But now he is remarried and wants to be "civilized." So now comes this invitation on an engraved "mr. and Mrs." card.

I suppose his wife is curious to meet his ex-wife. The trouble is my wife is curious to see his new wife and wants us to go. How are we supposed to act?

A. Happy. After all, this is a competition in which the idea is to show whom fate thought it right to reward. Your job is to look at your wife with the same expression that the detectives caught on your face eight years ago.

Q. I am a 30-year-old mother of two boys. I know several tean-agers in the neighborhood who babysit for us. They are reliable and enjoy the children. (Or I wouldn't use them!)

Many times they stop by to talk and ask advice on teen-age problems and visit after school. I'm alone a lot, and it's nice when someone drops over.

The problem is some have stopped calling me "Mrs." and have switched to my first name. My husband doesn't like it.

He became livid when I told one girl she could call me by my first name. I did this because she is a close friend with the college boy next door (with whose family we are close) and I felt silly when he called me by my first name and she called me "Mrs." when they were here together.

Another girl just switched to my first name because she decide to. I didn't like it. I'm friends with her mother. What can I do?

Basically, I think it's no big issue, but my husband thinks I'm being a jerk, these teen-agers won't respect me and I'm "older" and should be more formal.

Needless to say, no one calls him anything but "Mr." They wouldn't dare!

A. Miss Manners is having a most peculiar reaction to your letter. Most peculiar indeed.

In theory she agrees with your husband. There is altogether too much blithe usage of first names -- automatic assumptions of what ought to be the privilege of intimacy. The equality implied in the use of first names between generations does indicate a lack of respect for age or an attempt by an older person to seem younger.

However, in Miss Manners' heart she knows you are right. There is no disrespect intended; that is evident from the fact these teen-agers seek your advice.

It would be a slap in the face at this point to insist on making such a relationship more formal as informality is general these days and your young friends have probably not been taught anything different.

Could you acknowledge that your husband and Miss Manners are correct in this matter and then go on doing as you have been doing?

Q. A young woman from my office who lives near me takes the same bus to work every day that I do. We have even occasionally paid each other's fares when one of us didn't have the exact change. Since we work at the same place, naturally we get off at the same stop.

For reasons I don't want to go into, I want to be very, very correct with her, but always letting her go first has been awkward. When we get on, does it depend on who pays the fares? How about getting off? She seems to stand back then, and one of these days we're going to miss our stop.

A. A lady gets off a bus after the gentlemen with her, although she boards the bus before. That way, if she can't make the steps in either direction, he will be there to catch her. (Don't blame Miss Manners for these rules; she doesn't make them up.)

This order need not be violated if she pays both fares. She merely fixes the bus driver's attention with a half smile and nods toward the accompanying gentlemen to indicate the financial relationship.

Q. Don't you think that nowadays, in modern life, the old-fashioned custom of the condolence call is out of date?

A. Why is that? Is it because people don't die any more, or is it because the bereaved no longer need the comfort of their friends? Miss Manners is always interested in hearing about how life has been improved by modern thinking or technology.