To clarify, I was not friends with H while he was seeing OW, I didn't see him at all during that time.
I was actually friends with the OW, I know it sounds kinda strange but she kept contacting me and to start with I was really angry and really bugged and quite attacking ('why are you sleeping with MY husband?' etc), but the more she talked to me, the more I realised that she was a really lonely person and also, I realised that he hadn't told her anything about me or the kids or the sitch, so when it was in court, she was merely defending him out of ignorance.
She apologised to me after she became aware of a few things. I never thought it would last anyway as she has had 4 husbands and was going through a D with hubby 4 when she met my H, hence her attraction to him.
I also knew he still loved me so this helped me have a friendship with her without anger. I have a few common interests with the ex-OW so we were able to connect on other levels.
Sometimes it bugged him, other times I think he was impressed that I could be friends with her. Sometimes I wonder whether he put her up to it, being friends with me, when I was 'dark' with him, so then he could milk her for info on me.
She has emailed me and asked to maintain a friendship after she moves back to Ipswich with her new bf. I don't really want to as I want to close that chapter but I didn't want to hurt her feelings so I just said 'I'll think about it'.