So once Flattie had confided to me that she had managed to convince the hubs that he was better off without the wife, I felt I needed to intervene. I felt it was unfair to let a plot I had seen hatching in front of my eyes for two years, ONE I had actively encouraged by saying stuff like "Love comes in many shapes and sizes", "This stuff happens", "Maybe you should talk to her/him/together", "Maybe you should take your distance". And it was I, so to speak, who started this whole alternate-loving thing in my circle of friends.
So I talked to the wife and told her that she should not allow Flattie invade her privacy like that. Previously she had already said that she does not want to discuss her husband's treatment plans with her, and that she is taking charge of her hubbie's treatment, and that besides, he was not so unwell as Flattie thought. Flattie said that her husband was lying to her all the time, that he only told her things about the wife he resented and how badly he felt about their relationship. She has been telling this same thing for two years but only now to her face.
Flattie has severe paranoid thoughts about her rival. She for example thought that the wife was plotting her downfall, trying to separate her husband from the only one who truly understands him because the wife was a petty, envious soul who just wanted everything for herself. I said she was projecting her own negative qualities and fears onto this other person, but she said I was abusive and controlling myself.
Now Flattie has decided she wants to be friends with the wife so they can together move into taking better care of the hubbie. I told the wife that what I see happening is basically Flattie moving in to secure her place as the primary or "first wife". The wife had already decided there was no need for the two to be in contact, and I supported her in that and said that imho, people like Flattie won't stop unless you break off all contact with them and explain to them why, then refuse from "communicating" in the foreseeable future.
Me: bi female in my twenties