Glad you updated Loves - I had been so worried about you. Your friend's view is really illuminating. Perhaps she will also idly question her DH as well to see if he knows anything? Also, at least you now have an ally in the camp.
In your shoes, I still wouldn't confront until some other evidence comes to light - I really think he will deny it. If all depends on what you can cope with Loves - and I can see that to an extent, you might want this resolved before you go away, but if it does all come out, you two will need to talk.
I also wanted to say to you that if there is an admission, or a discovery and then an admission, you don't need to make your mind up straight away. You should see what he wants to do - watch whether he does it - and then decide. On discovery, you just need to hear the facts. You do not need to tell him your next steps - and believe me, you will need that thinking time.
So my position on discovery would be: tell me the facts, tell me what you want to do - and when I've heard it all and had all my initial questions answered, I'll get back to you. There might be many more conversations, over weeks or months if necessary, before you say what you want to do. It doesn't have to be an instant decision - and in many ways it shouldn't, either.
Of course it will be worth working out what you can and cannot cope with - that is sensible, but don't let this influence whether you confront or not. Where your friend is spot on is that there's no way of knowing how you will really react if it turns out this is mid-affair, or if he wants to leave you for her. None of us knows, until it happens to us, how this awful thing feels. However, you might need someone to talk to - so have in mind who that will be (as well as us!).
Also, you know your friend - it's not clear how well actually - but I do wonder whether this was the "safest" way for her of warning you. She told you that OW was predatory, she told you that you're right to be concerned, she seems to think he might well be having an affair based on what you've said - and is advising you accordingly. Is that possible?
I would wait to see how he is tonight - first see whether he initiates the conversation that should have happened last night. If he doesn't - and appears to be avoiding it - I'd wait until long after he goes to bed and get to work on that Blackberry, his car and his laptop.