They are my friends. One of the wives was my college roommate. She was the original wife. She and her husband was married for three years before they met the second wife, or mistress. Their relationship started from threesome. They are all swingers. The wife admitted to me that she was bisexual. That is to say, she is interested in male and female both, but she didn't realize that until the first time she and her husband had a threesome hookup with the mistress. They met at a party of their common friend. The mistress was bisexual too. She was invited by the couple to have a threesome dating. She agreed. After the threesome, they couldn't stop it. There were more threesomes happened. Eventually, the wife discovered her sexual orientation and fell in love with the mistress. His husband also was attracted to her too. But they didn't know each other and they were afraid to tell.
Until one day, they were talking about the mistress. The wife found that the way of her husband talking about the mistress is just like the way he talked about herself. She gradually realized that maybe her husband was falling in love with the mistress. She was very sad, but also felt jealous of them both. They confronted. They even tried divorce, but the husband didn't agree. He said that he would never leave her for another woman, even if he had some feelings for her, he could get rid of them. The wife had mixed feelings, both relived and sad. Finally, she came out to her husband. She admitted that the reason why she was so angry was that she also had feelings for the woman. Her husband was shocked by it. However, they still had love for each other. they couldn't imagine life without each other. They chose to forgave.
Somehow, they reached an agreement that they were willing to welcome another woman into their life. As expected, the woman said yes. I witnessed their proposal. A couple proposed to a woman. I can only say that there is no certainty for everyone. There is no absolute right or wrong. Can you say that they are wrong? They have been together for over two years. As far as I know, there have been no major trouble in them. They are just living their life in a different way. You may say that you don’t appreciate such way, but you can’t decide it is wrong. As soon as it fit, it is right for you.