Karen, so sorry to hear this. I could only try to imagine the type of hurt and anger brought about when finding out OW was/is actually someone you thought of as a friend, or even just an acquaintance. What a b*tch! Sorry but I had to say it for you.
You're right though, H will most likely be angry, but you know what? It's his own fault. If he gets nasty with you, stand up to him and say something like, "I realize how upset you are by this, but if you intend to be rude, vulgar, etc with me, let's discuss this at a more appropriate time when we can both talk as rational adults." Then walk away. Give him time to cool down.
Don't become upset with yourself. Many of us probably would've reacted the same way. Gotten p*ssed and did something about it. We're only human.
Be strong. Be patient. Be calm. Smile.
(((((((Hugs)))))))
Getting over a painful experience is much like crossing monkey bars. You have to let go at some point in order to move forward. ~ Joseph Campbell