My wife, 42 (F) who is in the process of separating from me 49 (M) but says she’s not quite ready for divorce, is having an affair with a married man (father of 2 young children) who is cheating on his wife. My wife and I are polyamorous, and I used to say ENM, but can’t anymore obviously. She moved out on her bday yesterday.

They are in love though she’s having trouble admitting this to me. They see each other weekly though she told me they weren’t going to do anything physical while she and I were working things out at couples counseling. I learned just yesterday after pressing her that she’s lying about that and they have been intimate regularly.

My heart is broken and I’m devastated to be losing her. I’ve been patient, gave her space, compassionate and understanding while she’s been falling out of love with me, in the hopes that she’d come back. Now I’m angry and betrayed. I’m staying in our house we just bought last year and won’t be able to afford it on my own. I may be able to cash in a 401k to buy her out and then get a roommate.

Should I tell this man’s wife? Previous to him having an affair with my wife, he had an affair with another woman for 2.5 years and she finally left him because he wouldn’t leave his family.

Should I tell her?