Just some thoughts from the other side. My SA was never in real life, just on the internet. When we separated, W thought that gave her permission to do whatever, and a year later she still thinks that. Just know that it doesn't solve anything.
Don't worry about this OW, she can't hold a candle to you. And keep coming here to get some ideas on how to make sure of that, which is the point of GAL. It may seem strange that your H still wants friendship, but it's actually very good. Keep that going. Of course, you want to punish him and be vindictive. But when you feel that way, read articles like this, it's helped me a lot:
Me: 30 W: 28 T 8, M 6 S: 7-27-2007 W filed (again) 3-2011 Served 8-2011 Responded, now dark "I have decided to stick with love. Hate is too great a burden to bear" MLK