I haven't had an affair but a good friend of mine has. She and AP were colleagues, and still are. I keep on and on at her to look for a job elsewhere. I've been a shoulder to cry on and when they have to interact with each other it's like reopening the wound. Can you find a job elsewhere?
Another issue with my friend has to do with the reasons for the affair in the first place. She is not satisfied in her marriage, and has said that deep down she knows it should end, but she can't bring herself to make that decision. I think this is a really big obstacle to helping her move on - in my own experience, meeting someone new is a huge part of being able to get over an ex. While my friend is unhappily married, she can't do that (unless it involves having another affair, which is not a recipe for happiness). So, I'd encourage you to think about the future of your marrriage (which you might have already mentioned on here - this is a huge thread and I haven't read the whole thing!).
While I haven't had an affair myself, I am unfortunately well versed in struggling to move on from people I've been pretty obsessed with :( It's true that no contact is essential, although I never managed to do that without the occasional relapse (I didn't actually contact them, just looked at photos etc, which was a bad idea in itself - no contact has to include no looking etc). It's happened twice, and in each case, it was a gradual and painful process of basically waiting it out until I could bear to date other people, and then the new person would push out the feelings about the old one, even when the new relationship turned out not to last.
(Btw in case anyone is feeling sorry for my friend's husband, he left his last wife for her, and he only did so when his last wife found out he was having an affair and confronted him. So, not deserving of much sympathy.)