Hi Lily - Please please please take the advice of GWN and SS. Our H's sound so similar (as do we with our quick non-stopping/thinking reactions!). I am working on this as well.
Absolutely DO NOT contact the OW in any way, at all. I know you WERE friends. Time to cut that loss and don't talk to her at all. I'd stop talking about OW and H from OW's H. It's not going to help you. Maybe tell him that "while you feel like it's a cruddy situation for all involved, they are two adults who are in charge of their OWN actions and are not reflective of either of you, and you would rather spend your energy and efforts into building a wonderful life for you and your S." Who knows, that might get back to H in one way or another. Or it might inspire OW H's to do the same for himself.
I would also stop emailing H. This is still a difficult thing for me (because when I see good signs, I want to email or call), but it absolutely DOES put pressure on him. Do NOT tell him HIS part of the problem in the relationship. He won't want to hear it. Yet.
I will say that the times that I did not contact H, he would reach out to me. Not always in a good way - but I didn't initiate it. Sometimes I can tell it's him wanting to connect with me to 'feel' secure (before he withdraws again). When I did call him, he grew defensive about having to 'check in' or 'report' what he is doing. None of which I called about. So bye bye phone! My 'angel' poster Kat on my board has been very gracious in reminding me that I need to speak to H as if he is a neighbor or the postman... Not overly friendly (I'm never going to run up to the post man and cry to him) Remember this!
If OW and H are messaging each other, or talking to each other - let it go. It won't seem so attractive when it's not forbidden. It's forbidden if you make a big deal about it. I know it's difficult to get your mind 'past' it. Here's a thought I'm doing right now: Busting out some pushups or lunges or something physical like that until you are too tired to think about it. Plus you don't need to change, it's good for your body, AND you get to blast out all that negative breath you are holding while counting (soothing)!
Me& h + S M: 13 t: 14
H moved 2/12. Own apt 05/12, EAs, PAs, gfriends, oh my! I'm done. 12/12
"I get knocked down, but I get up again.. you're never gonna keep me down" Chumbawumba