My best friend isn't into that sort of stupidity because that's what destroyed her first marriage. Her husband was sleeping around & she felt understandably cheated upon & endangered by the multiple partners and their potential sexually-transmitted diseases that he was bringing to their bed. When she wanted to have a kid, which requires unprotected sex, she realized she couldn't stay with him. Her current husband's first wife also cheated on him, so monogamy is important to both of them.

Other friends have been "swingers" and inevitably they got around to asking my husband if we wanted to join. They justify it as this woman's friend does ... you'll enjoy it; your marriage will be freshened by it; it shows you can trust one another. You'll end your marriage over it eventually. That's my observation from the half dozen couples I've seen over the years. All divorced, all over a new fling that became serious. Disease, pregnancy, shifting attachment ... it's all marital poison.