7 years ago DH and I went through a tough patch and he started an affair with my best friend. I suspected from very early on and caught them before they slept together (I'm absolutely certain of this). I ghosted her, we cut contact with her and her husband and stopped attending group events (large close-knit friendship group of interlappping friends from uni days) beyond weddings and funerals. Some of these friends cut us out for my "unreasonable behaviour" and others didn't. Best friend and her husband "kept" the friendship group iyswim. I never told anyone about the affair and reason for us stopping being friends.
DH and I got counseling, DH was incredibly remorseful and we made amends and are doing very well.
Yesterday we attended mutual friends wedding, DH was best man. Ex best friend and her husband were there. We were civil but kept away from them as much as possible. In the evening I was at the bar getting a drink and ex best friends husband came to the bar. I said a polite hello - he and I had previously got on well. He initially blanked me, fine I just ordered my drinks but then he turned to me and said "I just don't know what happened between you, how you could just stop talking to her like that. You were inseparable". To which I responded with "she had an affair with my husband, I don't think I was unreasonable". His face. Oh my god. He didn't know. After 7 years. No one told him. I had assumed, that like us they had chosen to work through it.
I feel absolutely awful. At the time I was really ill with PND and was barely functioning myself, I didn't really have the mental energy to worry about him (I was hospitalised shortly after). But now thinking back, the only people who knew were her, DH, DHs best mate (the groom) and the bride - because I told her. He's since text me asking to talk about it and I don't know what to do. Wibu to tell him after all this time? I'm going to talk to DH tonight once the kids are in bed.