Good to see that you got away and had a nice time. I'm sure the distance helped with your perspective as well.
Did you ever consider that maybe husband is hoping that you will do all of the dirty work? I just can't figure out why else he would say and do the things he does. Like you said, he's already with the OW, and he knows you know, so why is he draggin his feet? Mine did the same thing. Well heck, not just mine you read it all of the time. Some guys just get a divorce because they don't want to be with that person, period. Others have somekind of ulterior motive. They don't want to be seen as the bad guy OR they don't want to burn bridges until they're certain. Somethings definitely up with him or he would have found the mediator by now. That's not so hard to do.