"Platonic friendships can be richly rewarding," says psychotherapist Alan Loy McGinnis. "But if one or both of the friends are married, they must have a solid marriage to bring it off, since sex is in the air any time a man and woman are together."

He offers these six suggestions for "keeping sexual feelings under control and still enjoying deep friendships":

1. Don't trust yourself too far. Most people experience an ebb and flow of sexual desire. If your sexuality is at flood tide, exercise extra caution.

2. Select companions who have strong marriages themselves. If your friend is hungry for love, it may be very difficult to keep the relationship within bounds.

3. Be sensible about when and where you meet alone, since some settings are more sexual than others. Lunch, for instance, is less likely to lead to trouble as dinner by candlelight.

4. Talk to your mate about your friendships. When meetings become clandestine, it's a danger signal. Either bring yourself to tell your spouse about the progression of the friendship or get out.

5. Draw a line for physical contact. Find the amount of physical affection that is safe for you.

6. Bail out if necessary. Sometimes, no matter how hard you try, the friendship gets out of hand and you know where it is going to lead. If your marriage is precious to you, there is no question of what must be done. However great the pain, you back away.